I have spent way too long painting a couple of rooms in my apartment. I bought a couple of buckets of redish-orange paint from Wal-Mart only to find it took 3 coats versus 1 coat of a Benjamin Moore. Now, I am removing the painters tape from the Wal-Mart red only to find out is taking some of chunks of the 3-coat latex paint. Grrrrr.
What products, goods, or services should not be bought on the cheap:
Health insurance (HMO instead of PPO)
Televisions, DVD players
Markers and pens
Cologne and perfume
Doors and windows
A few others will probably come to mind later on...