This year I have tried to cut corners and save a dollar here and there, and one way I decided to do this, is to use something a little less expensive than the plastic trays from the hardware/garden center to place the peat pots in.The dollars stores are a great place to start, in that they sell aluminium pans, usually 2 for $1 and wooden clothes pins.
I came up with this easy way to label a whole pan of pots of the same kind of plant, using a simple wooden clothes pin. Use a permanent marker for the name of the plants and date the seed was planted, and squeeze the lip of the pan so it lays flat, and the clothes pin will stand upright. Couldn't be easier, and you can reuse the pan and named clothes pin again next season, (that is if you grow the same kind of plants). I suppose you could paint or use whiteout over the label on the clothes pin and reuse it to.