Covering the ground doesn't need to be expensive. I get loads of cardboard from a local builders merchant. Some people use layers of newspaper, but I don't get on with it. Whatever you use it needs to be held down, tent pegs, fleece pegs, bricks, large stones, bits of paving, are all good, and have other uses later on too.
If you can get your hands on a load of well rotted manure that is pyralid free (Your own is probably the most likely) you can grow no dig potatoes, with almost no preparation.
Cover the ground with cardboard, then a thickish layer of manure (must be well rotted or you will have scabby spuds) and plant direct into the manure. If you need to earth up more, you can use straw, but you need to wait until the plants are more than just little shoots, or it will get blown away. When they are full sized, finish off the earthing up with something that stops the light, e.g. more card, grass clippings, mulching fabric (if it's thin stuff use it double thickness, wilko's, at least last years, is decent stuff, and for this one layer will do.) earth, upsidedown turves, even more compost or manure, w/e
I
really like this method, it's much easier than normal potato growing, the spuds are easy to harvest, it's just as effective at clearing new ground as the normal method, and you get lovely conditioned soil at the end because when you harvest the spuds, you incorporate all the organic matter. :happy:
Also, if you are late like me (I only just got mine in) and your chits are long, they are less likely to get broken off, as the manure is soft.