Go to ebay and look up
MEMORY CARD DUAL SLOT ADAPTER MICRO SD TF to MS PRO DUO
That. It's let's you use 2 micro sd card into one memory card
I've purchased from this guybefore and it's only $4.
Then just look for micro sd sales and buy which ever you want.
I found two, 16gb micro sd cards at target for $15 each.
They had a 32gb deal for $20 around christmas time. I didn't get it though.
So you can have 2, 32gb cards for 64gb memory or 2, 16gb cards for 32gb memory.
I recommend you get your micro sd cards from a reliable source. No third party ebay china sellers. I don't want you to have a lot of save files and then one day lose them all. That's on you though.