sure, they will quote u low prices to tempt you first but after u agree to buy, they will tell you this is a 'bundle price' only available if you buy together with a bundle of accessories which will boost prices to 400+
some will then ask you to 'add ram' (no such thing as adding ram) or 'mod' your psp for an additional 50-$100 (if you purchase your psp from reputable sources, it will already come with AlexDark's newest firmware for free, there is no such thing as 'modding' the hardware of the PSP) you might end up paying 500+ IF YOU ARE LUCKY. then they will tell you your psp set doesnt come with a battery (while it actually does) and they will add $70 more and it might add up to $570+
there are others in hardwarezone forums who paid over $640 for a psp from SLS... Don't you think its ridiculous when you can almost get a PS3 for that price?
what 'reputable prices' are you referring to? Qisahn is selling for $280 currently, and the market rate should be around there and it is considered to be quite affordable.
I can bet that you will never walk out of an SLS store with a PSP at $270.