i don't think there's free wifi everywhere in Prague. i did get free wifi at my hotel, at Starbucks, and I think at the airport too.
1000 euros? i guess it depends if your hotels are already paid for via credit card, etc. i didn't spend more than 250 euros cash over 7 days, but that was because most of my purchasing was via credit card.
When I look for the hotel, I will check if I can get a wifi connection from the room before I book the room. I will go to the room n test. I will try to get a room facing the main street