There are no "cheap" cues worth investing in. Hype is hype, a fool and his money are easily departed.
Buy what you like playing with. If you are lucky, it might be worth a bit more in time - regardless though it will always be valuable to you if nobody else.
An example would be any Mark Bear fullsplice cue. I was fortunate enough to pick one up for 300 bucks six months ago. Mark's reputation as a fullsplice cue maker was well deserved. This particular build is no exception to how solid and well balanced his cues are. Unfortunately Mark had received his wings and the cues he had made are all that is left. IMO when compared to others with bigger "names", Mark is "underhyped" if all else - just do a search for any sale threads - nobody sells their Bears. If after 30 years my Bear is worth something significant, I wouldn't be suprised. If it's not worth much more than I had paid for it, I wouldn't be disappointed in the least - happy actually, that I didn't waste 3k on a dufferin.