The machine processing concentrates are not that expensive and should be fairly long lasting. The fixer should last over two weeks depending on use; you can also replenish the developer, making the whole process fairly economical. I've set up my Thermaphot ACP 505 (20"/50cm wide) machine for processing only a couple of hundred 8x10"s. An added bonus is that you can keep your hands dry and clean for working with the enlarger and negatives.

I should point out that these machines are designed for processing resin coated paper, not fibre base.