i'll take a stab at it, but there are way too many variables.

assumptions:
1) plot size = .5 ac.
2) lime needed but not too much, say 1.5 T/ac.
3) fertility ok, but needs some fertilier
4) seeding clovers at 3-5#/ac.
5) tillage is no "out-of-pockets cost"

If you can get the lime in bulk (back of a pick-up or dumptruck) you will save a lot of $$. going rate for bulk is ~$25-30/ton. If you need yo get bagged lime the costs will be considerably more (~$3-5/50# bag). You shouldn't need much fertilizer at a minimum you will be looking at ~200# of a started fertilizer (total costs ~$50). However, you may want to go with a blended mix with lowre N and higher P for the clovers. Seed will be ~$4-5/# for good Ladino clover and red clover will be ~$3/# (total cost for clover seed = ~$25). You may want to put down a cover crop of cereal rye (that's cheap - 100# for $10). It won't cost an arm and a leg to do a .5 ac plot, but there are mant variables to consider. First and foremost, take a soil sample and follow the recomendations.