UPDATES, some of which prove those who post comments are pretty darn smart:
I saw 25' of weed barrier for $7 at our local OSH; if you spread this over 7 bins (a good estimate), it's $1/bin, bringing the total to under $15, including the tomato plants.
The clear bins DO promote some algae. The real one I have (green exterior) just got dumped out, checked and cleaned and has no algae in it. My recommendation - go with something other than clear if you can find plastic you trust.
If you drill or cut holes for the top, make them bigger than you think they should be. I had plants rub against the cuts, and, well: cut plants. So, I have put some paper around the surviving plants (the plants are too big to take out to re-cut the lid). I'm trying to reseed in some of the holes, which should be interesting.