I went to Kansas restaurant last night (US$25 for a full steak meal and pint of beer), high-end Rosa Negra in San Ysidro night before ($25 for nice seafood risotto dish with a glass of wine), filled the gas tank for my fiancée, ($50), paid my basic Cable TV.internet/phone monthly bill (90), bought 30 tabs of 5 mg Cialis (90 - which in US would cost 300)..... I have been coming to Bs As off and on for the past 40 years and bought an apt here 10 years ago.
Gone are the days of the $5 steak dinner and $1/ hour maid that had been prevalent in the past 20 years. Prices now approach but are still somewhat less than prices prevailing in major US and European capitols. You can still eat out well a for a lot less than in NY (where I reside part-time), Bs As taxis are still a heck of a lot cheaper and so is housing (not top end hotels). My NY maid is 25/hour. My Bs As maid is 6 (and I pay top dollar). Imported high end clothes and electro domesticos remain relatively expensive as they always were driven by import duties.
In short, tourists with USD will not find BS As expensive because things tourists spend their money on (rented apts/taxis/restaurant) are still comparatively low priced. However, if you found Spain expensive in the past year even with the very strong USD vs the euro, you might feel otherwise - but then everywhere will be expensive for you.