Unfortunately there isn't an easier way as there is no way to sort based on price, nor is there a way to filter based on price to that particular level of granularity. So the only way on GOG to do it is to read through 74 pages of games, probably stopping to take an Ibuprophen a few times.
There is another option though, which is to use the 3rd party MaGOG search engine made by forum regular
mrkgnao which lets you search the entire GOG catalogue in just about every way imaginable.
http://www.an-ovel.com/pages/magog.php You can tweak the various search options and filters and probably find something useful to narrow things down and create a game short list, then read their pages on the store etc. and narrow it down from there.
It's really too bad though that GOG doesn't have better more advanced searching and sorting mechanisms baked into the store. They don't need to add the full complexity of MaGOG to the store as that'd probably scare a lot of users, but they could sure use some improvements that add more options for sorting and filtering in a user friendly way for sure.
Sometimes when a sale is on, I want to see which games are $5 or less sorted lowest price to highest price and I often just give up and don't even bother looking. MaGOG can be used in cases like that too but the results don't always match due to time lag of the search engine polling the store not lining up with short term promo prices and other factors. Still MaGOG is great though and the best thing we have for sorting and filtering the morass of games here.
Incidentally, if GOG *did* have a "sort by price ascending/descending" and "filter to only games within the following user supplied price range [$0.xx] to [$0.yy]", I probably would have spent $200+ more here in past promos whimsically because it'd be too easy to find more games I don't really need at rock bottom prices that I just couldn't pass up. So in a way GOG's lack of sorting/filtering options has saved me even more money, another reason to shop at GOG.com!