Google XXXXreviews whatever you are looking at obv.
Definetely spend the $20 on a CARFAX report(unlimited)
Honda or Toyota are the best used cars.
Check the tires for even wear all around
Make sure the engine coolant looks good.
Check the Oil/Trans fluid too see if it is burnt
Check the rugs too see if they are wet, if they are =water leak somewhere which is a big pain in the ass.