Portland, Oregon based label Mississippi Records has launched its own website and is starting a subscription series. Send Mississippi any amount of money between $68 and $300 and they tap your funds to send you each new release until your coffers are empty. Once your money runs out, top it up to continue receiving records. They're accepting cheques and cash (no Paypal unless you're overseas, on matter of principal which you can read about in the FAQs).
What you'll receive is a copy of each release as it comes back from the plant, which Mississippi estimate runs to around three per month, but does not run to a regular schedule. Send back the form on the site to customise your subscription to particular genres, and you can send a record back if you don't like it (although you'll have to pay for postage yourself). Questions, including information about international shipping, to email@example.com.
More details, forms and FAQs here.