Don't buy a second SSD. If anything buy more RAM with the money you would've used on a second SSD, RAM is still an order of magnitude faster then SSDs. Ideally you won't ever use pagefile or at least very infrequently, it's always slower then using RAM. It's good to have it for emergencies sake but in that case you don't care about it's speed so much so either the SSD or HDD would be fine. I prefer using my HDD because it frees up a little more space on my SSD.
EDIT: Just noticed you're concerned with more than just pagefile. I've moved pagefile, hibernation and all temporary locations (as well as Users and ProgramData) on to my HDD off of my SSD, you can absolutely do it. Personally I wouldn't bother with another SSD, it's not going to noticeably effect your experience much and the money would be better spent elsewhere.
Intel Core i5-4670K | AMD RX 480 8GB | Asus Z87-A | Kingston HyperX Savage 16GB 2400MHz CL11 | Samsung 840 120GB | Thermalright Macho | Lancool PC-K59