A few years ago when first moving to Seattle I bought a Queen spring mattress which has a thin memory foam pillowtop layer (effectively equivalent to a mattress pad). Less than $300. I've found it to be much better than the pure foam or pure spring beds I've experienced in hotels. I haven't had any overheating problems, except for when I briefly tried adding a plasticky bed bug prevention mattress cover which would have heated up any bed.

https://www.amazon.com/gp/product/B004LQ1RQU/