Another potential risk with buying a used bike is that it can be tricky to tell if you fit the bike (or if it can be made to fit you by changing the stem length/position and possibly the handlebar). If someone is a novice, I'd recommend not doing this unless they can get an experienced friend.
The possible pitfall of relying on an experienced friend is that ...
Rule of thumb: if you are an expert, you may be able to buy for 50 what is worth 200/500/1000, your experience will make up for the 150/450/950 gap.
If you are not an expert, you will for sure buy for 1000 what is worth 100/200/500. You will learn experience points worth 100/200/500. And you will lose a lot of money.
Yes, you may be lucky buying a good ...
I don’t think it’s a bad idea, but be prepared to repair stuff.
Things even a novice should be able to check:
Frame and fork without damage (i.e. no cracks or dents, nothing bent). Small paint chips or scratches are okay.
Shifting to all gears works.
Wheels are true, no damage to the rim or spokes.
This ensures that the most expensive ...