Another option, is to look for texts published by university presses or scholarly associations--these non-profits offer high quality, often at moderate prices. Or, you can seek out small specialty publishers with expertise in specific fields. Texts from these "niche" publishers can be both high quality and reasonably priced.
The search box below searches the sites of some large university presses. Additional presses and specialty publishers are linked below by topic. There is is also a long list of scholarly publishers that publish on multiple topics.
Some texts from scholarly and specialty publishers have won awards!