White clover. You can mow it each spring and it will keep coming back. Don't mow it to the ground, just clip the buds of the top.
As for a cheaper alternative, just go with a wheat/rye mix. It will come up green and deer will tear it up after the first frost.
Biologic, LabLab and such work, but you pay for the name, not the seed. Do some internet research and study the mixes and compare with others. You can find cheaper seeds that have just as good of a success rate. Find you a good mix of brassicas, clovers, wheats, oats, winter peas, etc and you will be in business. Just my $.02