My favorite gift idea that I recommend to couples low on cash is what I call a "relationship coupon booklet." Basically, you design coupons to give to your partner that allows them to "cash-in" on something at any time, such as a back massage, foot rub, get out of taking the trash for a week, extra hour on playstation, etc. You can really be creative on what the coupons are for as the ones I mentioned are only suggestions. It's a great way to have fun and save money. It's also really nice to enclose a card expressing how you feel for your partner with these relationship coupons.
Hope this helps. Happy holidays!