I just made that same purchase.... very well used ps3 at a pawn shop in Houston , TX for $50. (your results may vary...) This unit suffered cosmetic damage only. The original unit was big, but backwards compatible with ps1 and ps2 titiles. One the other hand it does not work with a few of the newest games... the motherboard just doesn't work with them... (don't know why... ask SONY)...
You can find so many of these units right now, you will likely find some at garage sales... but electronics in general will NOT hold up... its a physical phact. buy an extra one if you must... do not think its going to last a long time... even if it had an hour meter on the thing, you'll never know who (adult, child, teen, pre-teen, alien) or what CARED for it...!!! Controllers sold with these units are good indicators (if sold in bundle at a garage sale for example).
I immediately took it completely apart and checked for dust or debris that may have stopped or slowed air flow... replaced the small drive with a 1 Terra byte drive... (just do a quick google check to make sure you get a good drive... I am not sure if ssd's give you a speed boost... let me know)
It has been working quite well... this is my first SONY system... so the ability to play games on all three of the systems is a big plus for me...
And never underestimate the power of the garage sale... RockBank with drums, guitars, etc... banged up but good $20 a piece here and a piece there ha ha ha
Don't forget ! If you have a Playstation Plus with free games every month... you need lots of space!!!
Have Fun! Good Luck!
PS... the biggest thing for me was sound... I hate loud systems... That was what pushed me to the original PS3! The new 1terrabyte hard drive was not cheap... but the price keep falling...