Sweepstakes entries do not qualify as charitable contributions as determined by the IRS. While these may be considered charity ("tzedakah") according to Jewish law, the cost is not deductible as a charitable contribution or donation, and no donation receipt will be issued.

Friends of United Hatzalah Sweepstakes with a chance to win the Friends of United Hatzalah Prize along with entry into the United Hatzalah Israel Raffle
Official Friends of United Hatzalah Sweepstakes Rules can be found here