I just bought a SP101 the other day and I can't shut up about it. I went and shot it this morning and it is friggin great. Nice and accurate as well. Small and pretty concealable with summer clothes, with a sweatshirt it is a breeze. I got it with a bunch of accessories, hogue grips, holsters and speedloaders for $380. I saw a similar deal locally (private sale) a couple of weeks ago. If you are in a hurry it will probably cost you but if you can wait you can probably find a good deal. The GP100 is a sweet gun as well, and more for general purposes. If concealability is the main concern go with the SP101. If you want to open carry it and punch paper at 25 yards, go with the GP100 with a 4 inch barrel. It could be pretty concealed in colder weather clothes I bet.
Also, I find good deals on my state's shooting website (arizonashooting.com). I don't know if you have one but you could try and find one.