Hmmm. Isn't one of the ideas of a gallery to pre-qualify your traffic? People click through to your site because they're interested in that niche and content.
If you just buy blind clicks into your tour you'll probably have a much lower conversion. If you can find someone who will send reasonably targeted traffic then it may work.
Look at it another way - $50 costs for 1500 prequalified visitors is only 3.3c per click. Compare this with getting your visitors via a pay-per-click search engine.
Of course your time is worth money too, I've conveniently ignored that in my calculation.
