Welcome to the Zombi play pen.
here are a few parts suppliers I found that are pretty good on price and combined with used bike parts you can build a vehicle you can be proud of.
bearings etc. 3/4" Pillow Block Bearing, UCP204-12 | UCP204-12
new cheap bike parts. note it takes a while for them to get you your parts but well worth the wait.
Bargain Basement bike parts

LOTS of bike parts so you need to do alot of searching for exactly what you need.Clark's CMD-11 Mechanical Disc Brake - Front or Rear, 160mm, Black