So here are some things that climbers might like that mostly won't break the bank.
Battery Packs ($20-$50) and/or Solar Panels ($90+)
One of the biggest problems with being in the backcountry is the ability to recharge your devices. You should never plug a device directly into a solar panel. This will drain the device unless you have perfect light. Instead, you should consider charging a battery pack (sometimes called a battery bank). Then charge your device from this.
A battery pack alone might be enough to get you through a day or two. A solar panel might not even be necessary.
Goal Zero has several battery pack and solar panel options available. Check them out, here.
Chalk Bags ($10-$30) and Chalk ($2-$15)
Last year my mother bought me a chalk bag and chalk. She doesn't really understand what I do or why. And my chalk bag was absolutely falling apart. This was one of the best gifts ever. I was super psyched that my mother was supporting my climbing and it was also something that I really needed that I didn't want to buy for myself.
Chalk bags come in all types. You can get cool kitschy bags, and you can get plain jane bags. If you poke around on the net, you will find every kind you can imagine.
Skin Salve ($6-$20)
Skin Salve is one of those things that a lot of climbers don't buy, but they need. It's especially useful when people go on climbing trips where there is an intensive amount of climbing over a short period of time.
Kitschy Climbing Shirts ($15-$30)
There are a lot of funny climbing shirts out there. Cafe Press usually has a handful that are fun. Look Human has some good ones. And of course, there's always Etsy.
Harness Knife ($20-$40)
Multi-pitch climbers generally carry a knife to cut cord and webbing for rappels, but there are only a few out there that are climber specific. The Petzl Spatha is a great knife with a carabiner hole. The Trango Shark Nut tool is both a nut tool and a knife. And the Trango Piranha Climbing Knife is a nice compact knife for a climber.
Hot and Cold Water Bottle/Thermos ($15-$50)
A wide-mouth water bottle that also acts as a hot and cold thermos is an awesome gift. Hydroflask provides the most popular model right now, but there are a lot of others out there.
Subscription to a Climbing Magazine ($30-$60)
There are four major magazines that climbers read in North America. They are Alpinist, Climbing, Rock and Ice and Gripped. Alpinist is probably the best magazine for the alpine climber. Climbing and Rock and Ice are very similar to one another and cover everything from bouldering to big wall climbing. And Gripped is a Canadian oriented magazine.
Membership to Access Fund or American Alpine Club ($35-$75)
The Access Fund is an organization that lobbies for climbers. Their primary mission is to keep public lands open for climbing. This is an excellent organization to support.
The American Alpine Club lobbies for climbers, but also supports them in other ways. They provide two yearly publications: The American Alpine Journal and Accidents in North American Mountaineering. They also provide rescue insurance, lodging discounts in certain climbing areas, and grants for climbers.
Gift Card for the American Alpine Institute ($100-Whatever)
--Jason D. Martin