I like the comment about most music shops having less mandolins than yourself, which is very true for me too. Typical High Street music shops here in U.K. clearly don't see them as serious instruments and usually have a few token low grade ones on display amidst a vast array of guitars. The same tends to go for banjos, and you have to go to specialist shops to find any that are any good in terms of sound or playability.
As for cost, yes, you're paying about £1000 for a decent mandolin, notwithstanding any bargains on EBay and private sales, whereas guitars of similar build quality can be got for only a few hundred these days. All of which is ironic, because I started on mandolin as a teenager simply because it took me forever to save up enough cash to get a guitar, which were very expensive in those days. However, I have no regrets, because learning to play tunes on a melodic instrument first is an excellent grounding for taking up the likes of guitar and actually understanding music (keys, scales, modes, harmonic progressions, etc.) Or am I just being elitist?