Quite OK, but as well as issues mentioned above keep in mind that bringing a commercial electronic product to market may involve considerable <b>"compliance" </b> costs! Best start small & get a feel for such hassles & the agressive competition.
Some of the best commercial Picaxe applications have been local one offs, where a client specifically requests you come up with a solution that he'll pay going rates for.
One form ~2003 that springs to mind was a harbour side marina solar powered flashing light ID for boaties returning at night. Previously they were having troubles locating guide lamps against the glare of city lights etc, but the Picaxe powered ultra bright white LED system allowed coded flashes to inform of entrances etc. I recall this was set up by a sparkie in Australia (Sydney?) when Picaxes were first promoted, & he proudly mentioned " And what's more I programmed it myself". No doubt he turned $$ of parts into an invoice worth $$$. Stan