I get Sandisk Extremes, C10, U3, V30 (for 4k). These are still UHS-I (not II) and so are still affordable. so there's no good reason to save money getting slower cards.
64GB is enough for normal video sequences and photos.
If you do Hyperlapses with the "save DNG" option turned on (so you can post process them and create your own video from them in post-processing), you might want 128GB cards. Or if you tend to shoot long video, or are one of those people that turn on video recording on take-off and keep it rolling. And the 128GBs are not that much more.
You could get a 64GB now, then look for sales around Black Friday. Costco / Amazon sometimes sells 2-packs of Extreme 128GB for under $40.
I use a sun-hood over a tablet, so I can't help you with screen covers.
Chris