Romantic and inexpensive ideas for celebrating an anniversary include recreating your first date and setting aside an entire day or evening to spend quality time with your partner doing fun activities. Recreate your first date by wearing the same outfit you wore on that date and bringing your partner to the same restaurant or a place similar to it. Spend quality time together by talking, taking a walk, watching a movie or cooking a romantic dinner together.
If you live with your partner, create a romantic scavenger hunt by leaving clues around the house that lead your partner to an inexpensive, yet thoughtful gift. You can also place Post-It notes around your house with romantic messages on them. Place these messages on items your partner typically uses throughout the day, following his or her routine. For Instance, place a note on your partner's coffee cup or on the steering wheel of the car.
You can make your partner a homemade coupon book featuring coupons that offer things that your partner likes, such as a back rub, or that you do not typically do, such serving your partner breakfast in bed. Make the coupons redeemable any time between your current anniversary and your next one.