saying that you might as well have a look for either:
Both have built in preamps. A friend of mine who is a professional sound engineer was blown off his feet with the sound of the Samson mic !
Do you know if the mic you have puts out line level, Mic level (low Z) or guitar level (high Z) output ? It should say on the spec however until you know all about this Id not part with any more cash for something that might not not do what you want (like a preamp).
The reason I say this is that it is really odd (not necessarily bad) to have a 1/4" jack on a mic.
If the mic is outputting line level signal then a pre wont really help and may well just amplify noise.
If the mic is outputting Mic level signal a pre amp may well help boost your signal to noise ratio (defiantly good).
However most pres will be expecting an XLR type mic input and may not have a 1/4" that is setup to accept mic level signal. Or, if the pre has a 1/4" input it may be setup to accept Hi Z (guitar level) input which may sound bad with mic level signal coming into it as the impedance will be all wrong.
Anyway let us know and we will do what we can !
FWIW, I have always had positive dealings with eBay, though Im quite careful about who I deal with !