When buying from Used Selling shops/auctions

[mizu]

Is there any advice for when buying from selling USED items and Auctions when it comes to synthesizers?

I have a permanent ban for auctions until I'm high school (I think) And the only way to buy synthesizers are Amazon (they never sell vintage synths) and going to some USED selling shop.

I often find rare things such as a Roland JX for 30,000 yen (about 290$) a yamaha DX-7 for 3170 yen (about 30$) Are they safe to use? What source should I rely on when buying?

Thanks

[MitchXI]

I don't have very much insight on this,
However, if the place you're buying from allows returns or some way to try it beforehand, that's usually a good sign.

Sorry if that is a little obvious.

Also, a lot of the time, sellers will charge less for something because it's not in good cosmetic condition. If you don't care about how the unit looks then you're fine.