Jeppesen now offer database subscriptions for the GNS430 (and others) via Internet. You need to buy a “Skybound Datawriter” which is a device that plugs into a PC card slot on a laptop (or a PC card adapter on a desktop), then you download the database from the Jepp website and program the datacard with the Datawriter.
The cost of this subscription is substantially less than the regular mailed subscription. I bought the Datawriter, two spare datacards, and a one-year subscription for the dual GNS430 for less than the cost of the regular subscription. Subsequent years will be even cheaper since the Datawriter and spare cards are a one-off cost.