Everyone's on a budget. Given enough time and effort most of us eventually realize the biggest bang for the buck is a holistic approach that includes tweaks like HFTs and cones and interconnects and power cords right up there with the more traditionally recognized components like amps and speakers.
The thing of it is, there are now so many different products capable of producing so much improvement so cost-effectively that the greatest challenge today is to develop the listening skills and evaluation experience to be able to make effective choices. I mean, look: BDR Cones, SR HFT and Blue Quantum Fuse are all incredible values for the improvement in SQ they deliver. But the only way of proving that, and the only way of knowing which is best for your system in its present state is to, as folkfreak said, give it a try.
Just be sure to follow Audiophile Rule Number One: Never buy anything you haven't first auditioned, unless it can be returned no questions asked.