UPS offers a UPS My Choice Premium 3-Month Membership for $3 via coupon code "BTH5ZYHD3". At $1 per month, that's about $2 under the monthly price of a Premium Membership. (A 1-year subscription costs $40.) In addition to its normal My Choice services, it tacks on unlimited free delivery rescheduling, delivery to another address, and UPS SurePost upgrades. It also offers two free 2-hour confirmed delivery windows per year (additional 2-hour windows cost $8 each).
Of note, you can also get a 4-month subscription for $4 via coupon code "BU8CV8EH3".