$3,500 reseller about right, unless there is significant traffic.
PX is a common term meaning part exchange (where I'm from at least) if that helps.
Generally Q and X are considered less desirable letters, but this is only important in reseller sales as it is felt there is a lower chance of finding an acronym. This may be true in the English language, but X is a very commonly used letter in China for example, so maybe try marketing towards a non-English speaking area.
Nice domain, good luck.