Tom ... the "into" technique works within PL/pgSQL (or, in Oracle, in PL/SQL) only. You use it to put a value into a PL/[pg]SQL variable, not to propagate the value to the outside (Tcl) world.
A new ecommerce is sorely needed, though the modernized version of ecommerce3 with the service contract-based hookup to payment gateways will be a nice stopgap. You'll want to use these payment gateways, as Bart mentions.
I've worked with acs-workflow quite a bit over the past three weeks, ping me if you want some information on gotchas and hangups and the like. Short story: it's a great first cut and a sound foundation, but the current implementation has some (relatively minor) annoyances and shortcomings (many of the shortcomings noted on the aD "TODO" list for the package). Neophytos and I are both interested in improving it as time rolls on by ...
Using workflow is the Right Thing To Do but I might be able to save you a little time. Also I've been steadily committing a series of minor bugfixes to the package as I've been working with it. I've fixed the bugs I've hit as I've rolled on.
Another thing to look at is the form handler in the template system. It's very useful. I recently fixed the "currency" widget and datatype (it was only about 30% done in ACS 4.2 classic, apparently).
It's not tied into acs-lang but it should be possible to do so, and this seems the right way to make an ecommerce package know about different currencies. acs-lang ties formatting information to locales, and the form handler's widget is capable of dealing with specified formats, so off we go, right? (semantics, like figuring out how much an item costs in US$ vs. Euros is a [*cough*] simple exercise left for the reader).
