Honestly, it's not that expensive to fix those issues. the hinge requires a whole new shell, which you can find on sites like DX for like 15 bucks and as cheap as 10 bucks. the screen is like $5 on that site too.
Thing with all that is, if you've never taken one apart, or aren't ready with the right screwdriver (nintendo has a special one) then it's probably not really worth getting the system. Then again, there are a WHOLE LOT of guides all over the web that take you step by step.
it's really up to you.