Can I use my maaser money to enter a chinese auction, I would not have regularly given them, however they have a free gift that would be worth it for me to give them and get the gift rather than buying that same item in the store. Thank you

ב"ה Shalom Rav Ariel shlit"a in the Hebrew counterpart to this website said it is permitted to use money from ma'aser to buy a raffle ticket at a tzedaka institution as did Rav Vosner shlit"a. The same principles apply in both cases since ultimately you will be giving Tzedaka so it is permitted. (See Rav Vosner in the periodical Bet Halevi Vol. 11 Year 5757. And also Shevet Halevy vol. 5: 133.) Kol Tuv