§ 61.129 Aeronautical experience.
(c) For a helicopter rating. Except as provided in paragraph (i) of this section, a person who applies for a commercial pilot certificate with a rotorcraft category and helicopter class rating must log at least 150 hours of flight time as a pilot that consists of at least:
(1) 100 hours in powered aircraft, of which 50 hours must be in helicopters.
(2) 100 hours of pilot-in-command flight time, which includes at least—
(i) 35 hours in helicopters; and
(ii) 10 hours in cross-country flight in helicopters.
(3) 20 hours of training on the areas of operation listed in §61.127(b)(3) of this part that includes at least—
(i) 10 hours of instrument training in an aircraft;
(ii) One cross-country flight of at least 2 hours in a helicopter in day VFR conditions, consisting of a total straight-line distance of more than 50 nautical miles from the original point of departure;
(iii) One cross-country flight of at least 2 hours in a helicopter in night VFR conditions, consisting of a total straight-line distance of more than 50 nautical miles from the original point of departure; and
(iv) 3 hours in a helicopter in preparation for the practical test within the 60-day period preceding the date of the test.
(4) 10 hours of solo flight in a helicopter on the areas of operation listed in §61.127(b)(3) of this part, which includes at least—
(i) One cross-country flight with landings at a minimum of three points, with one segment consisting of a straight-line distance of at least 50 nautical miles from the original point of departure; and
(ii) 5 hours in night VFR conditions with 10 takeoffs and 10 landings (with each landing involving a flight in the traffic pattern).
Not sure what that would cost, but there's the minimum hours for you. I have no idea what helicopter rent for these days, and I don't really want to know, as I'd probably die of sticker shock. Best of luck to you.