Let's sum up.
Don't even bother going to the mt bike shop to get your entry bike with less than $900. Really $1,100.
The bright side- think of how much better off you are not ending up in the Hot Tub Time Machine, then spending $2,500 on a Mac 512k. Because when you get out of The Tub you might as well have burned the money. The Tombstone Mac is useless. The money spent though is now more like $5,000. That's a lot of burning in $20's.
Part Two. A Sadder Tale
Your "friend" has an 8 yr old mt bike in his garage. It needs some work but he'll give it to you.
This isn't good. Unless you have a barn full of X-Screams. (Even
@Bill Talbot probably only has 3-4 pair)
It would be better to take say the $225 you'll spend rehabilitating the 8 yr old jike and burn it. Maybe film The Burning in an interesting or stupid way, post on youtube and hope to recoup $1.25 in ads. You're still ahead of the game.
Now I know what these Wise Guys were doing. Contemplating buying an 8 yr old mt bike: