I'd agree with your friend's idea. You should be able to find .44 Special ammunition in most well-stocked gun stores. It will be expensive, as it is not as popular as the .44 Magnum, so not as much of it is manufactured and sold every year, which drives up the price. One thing that might help you in your search is the sport of Cowboy Action Shooting. Some of the folks who compete in these matches use lightly-loaded .44 Special ammo, so if you can find any Cowboy Action Shooting .44 Special ammo/loads, they will be loaded to low velocity, and might even be a bit less expensive.
If you can't find any .44 Special ammo in your local area, many of the online retailers should carry it; just look for the caliber's name in their listings.