I know this is not the answer you are likely looking for but here is my Long winded view on it, sorry ahead of time folks.
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AFAIK there is no dollar value, but I know I don't want someone to feel like they got the short end of the stick, handmade is ok, as is modded stuff (though most mods are a personal preference, so I might be careful with those).
I took what I could from the person's name that I was given and I did some detective work and was able to get a decent idea who I have from the list.
After that I looked at the persons posts to get an idea of what they are into so I can actually give them some things that feel they will genuinely enjoy and would possibly have picked up for themselves had I not of beat them to the punch.
Honestly, I sort of felt like a cross between a creep, a stalker and a detective during it all. But I know that it is for someone's enjoyment and doing so allowed me to tailor my gifts to the individual makes it worth it for me. It took me some time to come to this idea of researching who I am gifting, and until then I was entirely lost in regards as to what to give them.
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If anyone feels that this isn't in the spirit of the gift exchange and would prefer that even the gifters not know who they have, then I don't know what else to say aside from:
I honestly feel that when giving a gift, you should know the type of person and their interests so you can actually give them something that has some thought and heart behind it.
If that is not possible, then it is entirely understandable, Especially due to the nature of a gift exchange.
I don't want to know who is gifting something to me, but if they do what I did, I would understand the effort that went into to it, as well as the struggle to figure out what to gift blindly to someone you don't know the interests of.
Either way, there is an added level of appreciation coming from me after this exercise.