Tips for buying a secondhand guitar?

If it is an acoustic guitar make sure it doesn’t have any cracks or heavy bruises. Id f it is an electric make sure it sound good through an amp. Happy to help your son learn new songs on his guitar!

you only have to look at the "action" on the neck to see if it is both low enough? and none of the strings "buzz" anywhere on the fret board

Check neck of the guitar and check wooden shouldn’t be wet. And also you can check with tunner ( ample apps available in playstore and Apple app Store

The best but most expensive way to buy a second-hand guitar is at a guitar shop that sells used instruments. The advantages are that you can ask a salesman to play it for you, plus they wouldn't buy in a used guitar that has major issues. Buying from Facebook Marketplace, eBay, etc. will get you a cheaper price, but there is more risk of problems.

1st check no cracks or large dents(small cosmetic dents and scuff marks are fine)> 2nd all tuners work - one tuner/machine head could mean all six need to be purchased. 3rdly high action height caused by belly bulge - sunken on soundhole side of bridge and bulging on body side of bridge.

Well, I would like to say get a cheap but 'new guitar' if you can. I came across most of the issues on 2nd hand guitars is high 'string action', which means the strings are too far from the fingerboard, which your fingers need to press down to sound a note. I think this is the most important thing to pay attention to, of course, it is not acceptable with some surface 'cracks' or damage as well. It is not possible and does not make sense for beginners, especially kids or even pro players to fret hard and get pain to play with the instrument. We are supposed to enjoy music with the instrument, not get frustrated and any pain. But if buy from stores, when you have any problems, at least you can have a right to return, change ( we do usually ) or fix it. Ask the sales to do a check for you. At least have that kind of guarantee.

There are some decent new ones you can buy for the same price as a second hand one. I would say first ask all your friends if they have one to sell. Then you can try it out first. Next try charity shops. It needs to sound good or it will be off putting so always try or take someone with you who can play with you to make sure it sounds okay. Make sure there are no cracks. Make sure that the tuning nobs are not loose ( other wise it will keep going out of tune, but they can be tightened) , make sure that the action is comfortable ( not too hight or too low, this means the space between the guitar strings and the neck) If you have to press down really hard it is too high. If it's really low the sound wont be as good .

It depends. If you could bring the future tutor with you to try the guitar, that would be better. There are cheap new guitars that are also good - e.g. Yamaha C-40