I went to Target this weekend. While I was there, I stopped at the bike aisle. There were several things, and here are the things I found interesting and useful:

mini pump $10
helmets $17-22
U lock $15
headlight/taillight combo $27
wireless computer $20
wired computer $13
wedge pack (for the back of your saddle) $6
aluminum bottle cage $4
bottle with the above cage (combo) $10
bell $5

Really, most of this stuff looked outright decent, and the prices are good!