I can't say for sure, I assume that an influx of rain water and temp change would trigger them in the wild, not sure how much the rain water would drop the ph, but if you only need to go a little past 7 that shouldn't be too hard. They can live perfectly fine in your water, no changes required, the only problem is that the eggs may not develope because of the higher ph and hardness that is generally associated with high ph (calcium in particular). I am in the process of getting my ph and hardness down for my Lents, it seems to be working, they are showing signs of spawning - mine is down to 7.0-7.2 from 8.4, just mixed some RO and a BIG pile of driftwood.
I can't say on price, we are spoiled here, when I had cincta years ago, they were about $20 each at 5-6".