I have just one.  I've been mining mostly on Slushpool for 22 days, I have a reward of 0.00017938 BTC or currently just over 39 cents.  About 1 week before I got that I got a used Gridseed 80-chip G-Blade for Litecoin at $62 delivered.  It runs on nominally 100 watts and in the past 24 hours has earned 0.010524304440 LTC or $0.2396384120988.  Since I've had it online it's earned $8.08.

I think the best thing to do is set them up and forget about them, check once a day to make sure they're OK.  It's just a hobby, unless you've got free electricity (solar, parents, running at work, dorm room, etc.) the 2Pac won't quite break even.  There's a good calculator at https://www.cryptocompare.com/mining/calculator/btc?HashingPower=20&HashingUnit=GH%2Fs&PowerConsumption=7&CostPerkWh=0.12

Get practiced up and wait for Gekko's 16nm stuff.  Or really bite the bullet and buy an Antminer S9.  That can do like $3000/year profit, you just have to pay about $1500 for one.  Everything seems to get obsolete in a couple years because the difficulty increasing makes them unprofitable to run.  But solar panels are coming down to just over $1/watt, even at Home Depot.