Hey Fred...
If you're not averse to spending a few bucks (up to $100) then why not use a remote host? There are several that have the right configurations for zencart, that will let you host for a year.
One that springs to mind is lunarpages.com (and this is NOT a punt, just a suggestion). There are lots of hosts offering appropriate server setups for under $10/month.
I went this route a couple of years ago and the investment was well worth it. I learned zencart, php, and mysql sufficiently to start some serious webshops (I now look after 10 webshops for various clients - ALL on zencart.
In this way you focus on what's important - setting up a shop that generates income (unless your goal is to become a programmer, in which case carry on with your current route). Let the host fret about whether the php version is compatible with the Apache version and whether that's all compatible with MySQL and whatever else. YOU focus on configuring zencart as a SHOP OWNER, not a propellor-head.
Choosing a host that is well-configured for zencart will see you have your first shop up and running in a couple of hours (even less of you can FTP the core files over broadband).
Choose a host that's on UNIX, has C-Panel for backend admin, allows several databases to be set up at no extra cost, and has PhPMYAdmin.
If you want to learn about Zencart and not have to constantly fret over finicky programming on the server, then host your test shop somewhere.