I left a comment a while ago, but decided to expand it into an answer. I agree with those who think the frugal tag's unnecessary. In addition to what's been said:
My examination of the existing questions indicates that all of them are worded, or could be with a small amount of editing, in such a way as to render the tag unnecessary.
The most recent of those questions is March of 2013, so eliminating it now would prevent it from being used on new questions, at which point it would become more difficult.
I'll leave the real queries to those of you who know how to do them, but my cursory searches of questions with various forms of the words "inexpensive,""cheap," and "reuse," produced many more than just those few with the frugal tag, so that's a viable alternative way to find that type of information. Those questions also support the idea that the frugal tag isn't necessary, as they get plenty of attention without it.
I love tags! They're my favorite way of searching, both for information and for duplicates, so I think @Tea Drinker makes a good point. We also recommend tag-searches to new users. In this case, though, I don't think frugal's a helpful tag.