Savannah Stables said:

You can also look into just a pair of leggings, they tend to be cheaper than a pair of riding pants. I know people who ride in mostly yoga pants and leggings if they arent showing since theyre much cheaper and easier to find.

I ride a lot and I've found these Breeches are pretty comfy for much less than a "proper" pair of breeches are. I prefer the knee pad but they also have a full seat option. I think they're probably pretty identical to other breeches youll find on amazon in the 30-40 range though

Dover saddlery also has good breeches, I like their "unbranded" breeches and they go on sale quite a lot