Flirt4free is having another special discount currently for select members. Get 655 credits for $50! Regular price is 500 credits for $50.
These limited time offers appear from time to time, but are usually not as low as this one. This value is $0.0763 per credit. Credits are typically more than $0.08-$0.10 per credit.
Stripchat recently had some memorable discounts as well, namely the 50 credits free Black Friday sale and a 50% off the $50 package of credits ($0.05 per credit) this summer of 2019. Want more info. on free credits, check this link here.