Tbh, i think TAL has set its prices quite clever. They may not have the biggest name in audio app development, that's why a price of 100 € and above just wouldn't cut it. I think 60 $/€ is a fair price. But then, the definition of a fair price is different for everyone. That's why you should buy or not buy. Arguing about the price is kind of pointless, because the dev will surely not lower, or raise the price, unless the plugins sell better or worse."How should prices be determined?" To this question we could make a short and simple answer: prices should be determined by the market.
Btw, if you still think 60 $ is too much, or you're not willing to pay that, TAL plugins often go in the market place, so that would be the first place for me to look.