I've been somewhat interested in punched paper tape also. I see a lot of readers but few that actually do the punching. It also seems you need some knowledge of capturing data coming across RS232 as well as building an interface. Don't know how many of those units on eBay come with an rs232 interface.
You sound a bit dispirited! What computers would you like to use paper tape with?
If the punch/reader is RS232 (that's normal old fashioned async serial) then many (most?) vintage computers already have such a port so you don't need to build an interface. There is one on my Atari ST, TT and Mega. My old Newbury 6809 machines had serial interfaces. My new(ish) Core I5 Windows/7 PC now has two serial ports thanks to the wonders of E-bay and a PCI Express dual serial card.
Even if it doesn't have an obvious serial port then it may be possible to provide one with minor mods. Many machines have a cassette interface which is just serial data so it may be possible to extract he signal and use a couple of MAX232 chips to convert to RS232. If you do need to build a serial interface then I am pretty sure there are designs for almost everything on the net.
As for "knowledge of capturing data" then again many computers already have the routines build in. They were designed to work with ASR33 TTYs with punches, or with cassette tape interfaces and so there are routines to save to tape.
On Windows then you can use Hyperterm (if you don't have HyperTerm then there are plenty of instructions on the net on how to copy from an old Windows disk) to simply capture the data session to disk. (not sure if PUTTY will do the same on Linux)
If its a parallel reader then the fun starts. You may have to design an interface, and you may have to write code, but its not hard code....
As for punches, then there is a nice looking Facit on Ebay but I wouldn't pay $250 for something sold as untested. I paid around $50 each for my GNTs and one has a a dead hole on punch...
Dave