That's even more of a problem, nobody has the resources or the money to test the thousands of players in club rugby, many "supplements" are relatively cheap. As long as you're not dumb enough to post it to your own address and pay by credit card then it seems like it would be fairly easy to cheat. Everybody needs to remember that the only way to truly test athletes is random out of competion *no notice* drug tests. Anything less can be beaten by timing your doping properly. Even out of competition tests can be beaten by lying about your whereabouts. The WADA policy is that you get two "no shows" before any sanctions apply, that is where the testers turn up at your supposed location and you're not there. I'm not sure that procedures for non-olympic sports in this country would even be that strict. Do the testers always do their OOC tests at preseason camp? Time for some training in the mountains, etc.
There is arguably more incentive for people to dope on the fringes of professional sport. If you've decided to dedicate a few years of your life getting into a S15, NRL or AFL team then is a couple of thousand dollars a year worth it to give you the leg up you need to the glory/gravy train.
Think about how many tests have to be conducted to ensure (for example) that a base of 1000 athletes are clean. You have to test them multiple times per year and the cost of each test could be quite high if you have to drive out to their summer holiday house at Timbuktu, plus Lab costs, administration etc. At $500 per test (no idea on lab costs, but OOC testing will take man-hours) that would be half a million dollars a year, there are many thousands of athletes on the cusp of professional and olympic sports in Australia every year.
And on a related note,
There is an IRB report toting how many OOC tests they conducted in the lead up to the world cup. But if all of these tests were conducted at team training camps and hotels where athletes might expect to be tested then perhaps the number of tests isn't as important as the methodology for conducting them.
IRB report:
http://www.irbkeeprugbyclean.com/downloads/reports/AntiDoping2011.pdf