I don't think it's that expensive?
In fact, I think it's quite a bargain when you think about what you're getting - very high quality, industry-leading products backed up by a good, solid company history and amazing training. And, obviously the on-going support, etc. Plus even just the name shellac is a boon - many people request the service on the strength of that alone.
There are some things that you may buy in at a cheaper price - cotton wool pads are pretty much cotton wool pads at most price points (though I don't recommend the cheapest of the cheap!), bananas are pretty much bananas at any price point, etc, etc - but there are other things where it makes more sense to spend a little more in the beginning and do things properly. This is usually the case where you're spending a few pounds; it makes more sense to get the service right from the beginning rather than having to then buy another system and therefore wasting money.
You need to weigh up which service is going to be best for you and, ultimately, your clients. The best way to go about this is to research, research, research and try as many different products as possible. Then, and only then, will you be informed enough to make the decision. Remember though that this is your business (fair enough it's your hobby right now, but why start out and change halfway through?) and your name that is at stake so you best be sure you're working with products and companies that fit with your image and work best for you.
Finally, and to address your last post, I believe that training is the one area that should be thoroughly researched and not scrimped on.