I have built nurmerous rods now. One thing i can tell you is that buying any blank online can be very tricky. I have one good and 2 bad experiences buying what are probably "seconds". One broke on the first trip and the other was 2 different rods and so it was a pain in the butt getting that sorted. So #1 make sure you are getting a quality blank (online or retail). #2 there are lots of online stores where you will save a ton on components. There is one cork wholesalers in particular that can save you 50% on cork. I bought 6-7 rods worth, I am not sure if he would do it for a single rod. And ther is a guy on the island that seemed to have the best price on components and I have used him 2 or 3 times with great results...feel free to email me thru the link here and I can give you more specific info if you require it.
As well, I have maybe $200-$300 invested in equipment to build rods. Don't know if you have a wrapping station or rod turner already (expensive to get for one rod), if you need some equipment on a rental/borrow basis, send me an email.
Good luck, there is something a little extra special about landing a fish on a rod you built yourself so I can tell you you are in for a great experience. Just take your time, don't rush and you will have a beautiful end product I am sure.