There are some things we need to rethink relative to trying to do them on a budget, or not at all. Doing anything much past 100', maybe 120', with a single tank of air exponentially increases the risk of serious injury if a problem occurs. Diving to depths greater than I would care to ESA from without a fully redundant air source is on my "no no's" list. I think too many folks look only at the monetary cost when deciding what to do. The folowing statement scares me a bit:
"any dive that doesnt require technical equipment (ie mix in this case) can be done cheaper without it."
The scarey part is the definition of "require", it seems quite subjective ..... There are some who would say that since they can go to 200' and return on a single al80, that tech gear isn't required.... so why bother with the expense of it...
The real cost of cutting corners on gear/training, is that it can get you hurt or killed, ... and you don't get a second chance to do it right ..... Think about it... if you're already on a budget, what are the odds that you have enough of the proper insurance to provide for your family if you sell the farm down there... If you accept the added risk to yourself, have you provided for your family, since you Also accepted the additional risk for them as well... There is NO, "ooops, sweety, I screwed up, I'll make it up to you".
Diving is a lifetime of enjoyment, good planning and patience insure plenty of both.
Darlene