I'm a fan of microSD card slots. I know, I know, there's absolutely no reason to have this debate right now. You either prefer to have expandable memory or you don't particularly care.
If you're on #TeamGiveMeMoreCheapStoragePlease, then now may be a good time to head over to Amazon. Flash memory of all kinds is on sale there for up to 70% off. The 128GB microSD is going for a mere $29.99. The full-sized alternative is just $35.99. A massive 256GB SD card costs a bit more, at $64.99, but that may be enough storage to stick in your PC and effectively double the size of your SSD. Alternatively, you can grab a 128GB flash drive for $19.99.
Small sizes are available too, and they cost less as you go down. You're welcome to go that route if you're inclined to view carrying around over 100GB of data on a mobile phone as overkill.
You can browse the full selection at the link below.