It seems the mindset of the majority of used car shoppers is to buy a used vehicle from a large dealership that sells new and used vehicles.  Buying a used vehicle from anywhere is chock full perils and most people are looking to limit getting taken buying a bad vehicle.   Does buying at a large dealership really limit your exposure to buying a bad vehicle?   Used car salesman have bad reputation right from the start.  There can be bad salespeople at any size establishment.  Things that make it worse are lies, high pressure and the overall bad vibe from either the person or the vehicle.   I am going to point out several things that will give you more insight on how to avoid buying the wrong vehicle and maybe some things to think about on where to buy your next vehicle.
First I would like to point out that buying at a large dealer that sells new and used vehicles does not guarantee your deal will be hassle free nor does it guarantee that your car will be the right one for you or that it is mechanically sound. People think that at a big dealer that has a big service department that the used vehicle must be a good one.  It surely must have been inspected, fixed properly and fully ready to be put on the lot.   That is not always the case.  I worked at a dealership that when they bought or traded in a used vehicle they had a mechanic in the service department inspect the vehicle.  Normally these guys are not the same mechanics that are working on the new vehicles.  They do the inspection and come up with a list of things that the vehicle needs.  They hand that list to the used car manager who then decides which stuff they fix and which stuff they don't.   I can tell you from experience that there were vehicles on the lot that needed repairs and were done to keep the cost down.  It is easy to tell when a vehicle needs brakes or tires.  Most customers can tell by looking or driving.   Things that are less obvious or can't be seen or heard on a test drive are often left out of being handled. 
The next misconception is that all or most small used car dealerships are crooks or shady.   There definitely are a lot of bad ones out there so I can see how this one is easy to be in the front of your mind.  One thing that all dealers have in common is the fact that they want to make lots of profit and spend as little as possible.  Finding the right car is the most important thing that should be considered when looking for a vehicle.  Finding the right dealership is probably second.  Having a great dealership experience but buying the wrong car for too much money will still leave you in a very bad position in the end.  
Here are some things to remember and think about before buying your next used vehicle.
#1-In almost every Large dealership they have everyone get paid commission.  They need to keep profit margins high since several people are taking a piece of the action.  It is easy know understand that the salesperson takes a commission and maybe the used car sales manager but what most people don't understand it that other people are taking some of the profit. People like the Finance Manager, New Car Manager, General Manager, Owner, Office Manager and in some instances the Parts and Service Managers.
#2- smaller used car lots have less overhead and many don't have commissioned sales people.  They can have lower prices on the same used vehicles because they don't need all that extra profit for commissions and high building expenses.
#3 - Always have a vehicle inspected by someone you select.  Even if it is at a large dealership claiming their service dept already did a full inspection.  Remember it is not about what they did fix or maintain.  It is about what the vehicle still needs now(things they did not do) or things that it may need in the near future.  There is nothing wrong with taking it to have a second non biased opinion.  Any dealership that objects..........just walk away.
#4 If you have good/great credit you may want to avoid going to places that advertise Guaranteed Financing for Everyone.    I could write a whole blog this topic and why......Do yourself a favor and don't waste your time. There is not much good that will come out it for you.  Cars will be in disappointing condition and your experience will be less than desirable.
#5 - Avoid the dealers that need get your attention by crazy commercials, unrealistic deals advertised or junk mail that state " We need your trade.....Please bring in your 2005 PT Cruiser for Top Dollar" or even Test Drive for Free Gift - Win a Car!  I am surprised at how often people fall for this garbage.  No one ever has a key that fits the winning car.  They really don't need your old worn out trade.   You get the point.  NEVER FALL FOR THIS STUFF.....EVER
#6 - Read Google Reviews.  This no sure fire way to guarantee that you will get the right vehicle with a no hassle experience but it could save you time from going to a bad dealer.  You may see dealers that have lots of great reviews and a few bad ones.  What you want to look for is what the bad ones says.   It is easy for a dealership to encourage happy customers to write a quick review so that the bad ones get less noticed.  What is important to see what happened in the bad ones.  If several people write that their transmission or engine went out soon after they bought the vehicle then it should be concerning.  Clearly they do sell bad vehicles.  I have also seen lots of reviewers state that they were clearly mislead or the dealer never mentioned huge issues with the History Report.  Seeing lots of people complain about buying a vehicle with bad Accidents, Airbags Deployed, Salvage Title, Canadian or other major history report issues means they purposely buy these vehicles in order to maximize profits and take advantage of people. No matter how many good reviews that they may have does not make up for the fact they have and will sell bad vehicles to people when they can get away with it.  This is the perfect example of wrong car and wrong dealership.
#7 - Always look at the Carfax or at the very least Autocheck. Make sure the VIN on the report matches the VIN on the car.  Reading and fully understanding the history report way more involved than just seeing Owners and Accidents.  This will probably be another blog topic I will explain more in detail. Everyone likes One Owner No Accident Vehicles but in reality that does make it a better or nicer vehicle.  It is still important to look the car over and have it inspected.  Not everything shows up on the history report.  Unless the car is priced 40-50% off the Retail Value you will want to avoid: Salvage Title, Total Loss, Mileage Inconsistent Issue, Accidents involving Airbags Deployed, Vehicles that spent their life in Canada and Lemon Law Buyback.
#8 - Do some online research on the model you are considering.  It is easy to find certain years or models that have major mechanical defects that should be avoided.  
#9 - Avoid putting too much faith when different websites tell you a certain vehicles is a "Great Price" or "Good Deal"  Often they are missing options, have bad history reports, body damage, mechanical issues or even smell like smoke.  There is absolutely no way for a website to know what condition the car is in.  Since condition has a huge impact on value, how could they possibly know if something is a good deal or not.
Once you tackle some of these important tips you will get a general sense on what dealers not to waste your time with and which ones are worth a closer look.  You might be surprised to find a few small dealers that really can give you a Hassle Free Experience on a vehicle that has a great history report and is in above average condition both physically and mechanically............all at prices that beat the big guys hands down.