for a first time carrier, i recommend something small in single stack. i'm not talking pocket gun, just something slim and easy to conceal. the biggest enemy to concealed carry is the gun that isn't comfortable to carry.
having carried for a few years, i still only carry double stacks about half of the time. they just aren't as comfortable or as easy to conceal. if i am going to carry a double stack, it's almost always a polymer. they are just a little bit thinner than the steel guns.
in your price range, i definitely recommend the walther pps. it is usually my gun of choice when i'm going to be carrying all day (comfort), or when i'm going to be the center of attention (concealability).
if you can find one (rare, especially in your price range) the hk p7 psp is quite literally the best concealed carry gun in its size. it is extremely accurate and extremely easy to be proficient with. it is the also the safest pistol ever made. it's unique squeeze-cocking action is the key. its one drawback is its weight. being a steel pistol originally designed decades ago, it is nowhere near as light as the polys of today. given a good holster and solid, double-stitched belt, you won't even notice the weight.
a cheaper option for single-stack is the kahr line. they have a couple nice pistols for relatively cheap. i wouldn't choose the smallest, as it will be hard to hold onto, but the second one up is a great size for iwb carry.
if you're sure you want a double stack, you can't go wrong with a walther ppq or ruger sr9c. i personally choose the walther ppq, since my other carry is the pps. it just keeps familiarity of operation. the sr9c is one of the most accurate compact guns i've ever shot in that price range. it is one of the best values on the market. i have a cz 75d compact (pcr) as well. it's a great little gun, but for some reason, it is very uncomfortable to carry iwb (at least on the hip). i think it's the shape of the mag baseplate. it always seems to dig into my love handles.
the one sig option even worth looking at in that price range is an sp2022. i had one and didn't much care for it. the trigger reach was far too short to be comfortable in my hands. other people swear by them. if you decide to go this route, pm me. i have a really nice iwb holster for sale
the p250 is a waste of time.
stay far far away from any taurus or the s&w sigma or sd lines.
while bersa makes a great 380, i was less than impressed with the rest of their weapons.