How much did you paid for beer, tacos, hot dog in 70s on ice rinks?
That is an interesting subject. Prices in the 1970s in North America rose markedly with inflation. A 1978 Detroit newspaper article referenced these increases in prices for certain concession items at Red Wings games at the Olympia:
A bag of peanuts - from $0.35 to $0.50
Popcorn - from $0.45 to $0.50
Ice cream - from $0.35 to $0.50
Potato chips - from $0.35 to $0.50
Caramel corn - from $0.35 to $0.50
Beer - $1.15 (volume unknown)
Hot dogs - $0.75 each
Knackwurst sausage roll - $1.00 each
Another survey conducted by the Pittsburgh Post-Gazette in May, 1976 across the four major sports leagues in the U.S. at the time (MLB, NFL, NHL, NBA) unsurprisingly revealed that Madison Square Garden had the highest parking costs at $5.50 per vehicle (but, the article qualified, "almost no one drives to a Knicks basketball game or a Rangers hockey game"), the Montreal Canadiens along with the NFL's New Orleans Saints came in second at $4 ($1 USD = approximately $1.02 CAD at the time), parking was $3 at Chicago Blackhawks' games and "usually less than $2" elsewhere. The Detroit Red Wings' sold hot dogs at $0.75, the highest among all of the leagues, while the Toronto Maple Leafs and Detroit Tigers charged the least for soft drinks at $0.30 per. The Leafs and the Atlanta Flames and Hawks basketball team had the least expensive hot dogs at $0.35 each. I was mildly surprised to read that beer was unavailable at Toronto Maple Leafs' games (!) in May, 1976.