Good quality mattresses are expensive, so do look for sales. High-quality mattresses often go on sale for as much as 50% off. And if you’re paying $1000 and up for a mattress, that’s a hefty discount.
Ultimately, the only way to find the right mattress for the two of you is to try out several. If you’re changing beds because one or both of you is sleeping uncomfortably, then you may at least have a sense of what you don’t want in a mattress. So go to a mattress store with a good selection and name brands, and plan to do a little bed-hopping. Just keep your clothes on, please!