In a city where the going rate for an individual machine-based Pilates session runs about $100, achieving the workout’s Gwyneth-flat abs and willowy yet toned arms can be prohibitively expensive. San Franciscoľbased chain Pilates ProWorks (47 W. 14th St., nr. Sixth Ave.; 212-929-6106), opening February 15, cuts the price and the elitist feel. Rather than one-on-one sessions, the studio enlists FitFormer machines (a longer, slimmer version of the traditional reformer) for high-energy classes of up to a dozen students, led by instructors more likely to cue up Beyoncé than sitar solos. Additionally, the 5,000-square-foot facility devotes a second studio to barre- and cable-TRX classes ($35 per 55-minute class; from $225 for one month unlimited).