How much would you pay to spend an evening listening to live music under the stars with the gorgeous Franklin Park Conservatory as the backdrop? Sounds like a hot ticket at any price, but the truth is this perfect evening can be yours for nary a red cent. ProMusica’s free Summer Music Series returns to Franklin Park Conservatory and Botanical Gardens for three nights this week, Thursday, Saturday and Sunday. Come once, twice or all three times for some summer fun that is a feast for the ears, eyes and (when you pack a picnic) the taste buds. The fun starts each night at 7 p.m. with pre-concert music and garden-inspired children’s activities. Or stroll the beautiful grounds and commune with nature, before the music begins. Pack a picnic or buy some nosh from the on-site food and cash bars (note: no outside alcohol is permitted). Spread out your blanket and ready yourself for some spectacular performances. The music is the main feature, of course. On Thursday the ProMusica Chamber Orchestra with Chelsea Hart Melcher (soprano), Carlos Alberto Monzón (baritone) and David Danzmayr (conductor) will perform Mozart’s Overture to The Marriage of Figaro and Selections from The Marriage of Figaro, as well as Schubert’s Symphony No. 2. On Saturday night, the ProMusica Cello Quartet (without the orchestra) with David Danzmayr (conductor) will perform Piazzolla/Zamastil’s Concerto Para Quintento, Fitzenhagen’s Ave Maria, Piazolla’s La Muerte, and Beethoven’s Symphony No. 7. And on Sunday, the ProMusica Chamber Orchestra with David Danzmayr (conductor) will perform Bartok’s Romanian Folk Dances, Piazzola’s Coral, arranged for string orchestra, and Tchaikovsky’s Serenade for Strings. For more details, visit the ProMusica website.