Nope, no wifi needed. I already have Plus content on my vita. No worries.
From all of the stores ads I've looked through I have seen a total of zero Vita Memory card deals. And i've looked through Walmart, Kmart, ToyrUs, Sams Club, Target and Dell.
True. Amazon currently has them listed as:
4GB: $17.00 ($19.99)
8GB: $25.97 ($29.99)
16GB: $46.62 ($59.99)
32GB: 80.90 ($99.99)
Not too bad, but not amazing, either. I may just get the 16GB card, but I'm torn between that and the 32GB card. I usually buy 99% retail, but I got AC3: Lib digital, and I'm getting All Stars digital free with my PS3 version. So many other Cross Play games are making it more reasonable to go whole hog and get the 32GB.