I would go with your friend's bong. Not only is it cheaper, but you just said it was amazing. Your own question answered. I would love to have a friend make me a nice bong I enjoyed, rather than forking out for generic shit IMO.
aright...first off....for 35 bux ur not gonna find anything amazing..u might find a nice acryllic bong...but the metal slide will affect the taste of the smoke.. and if u do find a glass bong..it will be very fragile..i mean accidently hit it with the lighter and it might crack fragile...i would go for ur friend bong..... and if u even want to and the whole slide comes out...u can pick up a cheap glass cutter...kinda looks like a box cutter..u can gently shave around the circle where the slide piece was....of course tho u should get the slide piece first...so u dont shave off too much...... just my opinion tho
I would buy a new bong. 35 bucks in not that much an expense for something you can use a long time. Besides, if you buy new, you can get something you really think looks nice and fits your smoking style.
I have bought a nice acryllic bong of 30 cm for 30 euros and it is pretty sweet. A Bong like that is really easy to toke from.
I recommend looking for something with a shotgunhole. And a twist in the tube, so you can put ice in it (really sweet).
Edit: If you're pretty new at smoking, get a transparant bong. That way, you can easily see how much you smoke, in order to determine what your favorite dose is.