Tripods and monopods - To capture crisp, in-focus photos, a photographer must be able to hold their camera steady. To help with this, a tripod or monopod is a must. There are loads of ways to make a homemade tripod or monopod.
A beanbag tripod is perfect for outdoor photography when a traditional three-legged tripod won't work (for example, when the ground is uneven). Make your own beanbag tripod with this DIY project. If your Valentine enjoys outdoor photography and hiking, an alternative to the beanbag tripod is a walking stick monopod. Read DIY Walking Stick Monopod to learn how to cheaply and easily make one from home with supplies you probably already have laying around the house (or in your backyard). A Gorillapod is a flexible tripod where the legs easily wrap around objects such as a tree branch or table leg. Learn how to make your own Gorillapod here. Another version of a tripod that is easy to pack around is a string tripod, which you can learn how to make by reading How to Make a DIY String Tripod.
Studio Equipment - If your Valentine photographer is into portrait photography, you may like to consider making him or her a solid and stable reflector. The DIY tutorial How to Make a Rigid Reflector for Under $30 will teach you how with easy-to-follow instructions.
Depending on what you already have laying around the house, you can make a flash clamp for as little as $5, discover how with this tutorial on how to make a flash clamp.
Professional backdrop stands can be quite costly, unless you make your own. For about the same price as a box of chocolates, you can make a cheap backdrop stand for your significant other this Valentine's Day.
If your Valentine is into product photography or likes to sell things on eBay, read How to Make a Light Box For Free to learn how to make something they will definitely be able to use and will appreciate.