OpenSecrets.org has numbers for fundraising for Senate candidates (and House candidates):

As of March 31, 2010, John McCain (R, incumbent) had spent $16M and had $27M on hand.

J.D. Hayworth, who has moved up significantly in Rasmussen polls, had spent $0.4M and had $0.7M on hand.

See here.

The Arizona Senate primary is August 24th, 2010 …