Here are some basics:
1) The quality of your guitar and amplifier will get better the more you spend on them up to a certain point. In essence, you get what you pay for.
2) The quality of your first guitar/amplifier do not need to be spectacular as you likely won't know where the extra money went until you reach a certain talent level. That being said, don't get the cheap guitars that come in a package with an amp, the 'house brands' Sam Ash likes to hock, etc. If you're serious about the hobby invest in a cheap yet decent quality model. We can make suggestions based on the kind of music you like to play. I just see too many people trying to start guitar and get something that sounds so bad that they get frustrated and give up, when a little bit more invested could have went a long way.
3) Before you buy any guitar from a store like that, google the name/model and find out what 'online' vendors are charging for it as well as what they go for on ebay. Have this knowledge on hand. I have to say that for the most part, guitars are priced pretty much across the board for a new model, what can get you is the used price of a guitar however. This can be easily found on the internet and you shouldn't pay any more than that.
4) As far as bartering for a guitar, as long as you have the used price info you can easily say, "I really don't want to spend that much for this, I can get this online for cheaper, thanks for your time." I'd say most times they'll say "ok" and won't budge on it because I'm assuming that most commission based employees don't have the authority to knock the price down. This is my experience with it though, I'm not saying you should expect it. It's always worth trying to barter.. worst they can say is "No." What you CAN however get away with and I've done it for every guitar I've purchased through a store (usually through a private retailer, as I tend to avoid chain guitar vendors) is getting new strings put on it and having it set up. Most respectable vendors will fix any problems with the guitar like intonation, neck adjustments for fret buzzing and/or warped neck, crackling in the potentiometers (the knobs on the guitar), etc.
5) You should look for any of the following things when picking out a guitar:
a) Buzzing frets. Play every note on every string all the way up the guitar neck right in the middle of the fret and listen for vibration/buzzing sounds. A lot of times in chain stores like Sam Ash, all the 13 year old kids who love to play slipknot have systematically destroyed the setup of the guitar you're playing. This can be easily fixed by the dealer but you need to make note of it to inform them.
b) Plug in the guitar to an amp in a private room if possible. Dime the amp and test for how well the notes sing out. Sudden loss of sustain (how long you can hold the note before it chokes out), notes that seem to go out of tune, notes that 'fret out' or don't sound out as fully as they should are all things to look for. These can be fixed with a proper bridge setup and/or re-intonation.
c) Look down the neck of the guitar for signs of warping or improper curving. This is something that a novice probably won't be able to notice all that much but it's presence may give way to the problems to look for I talked about earlier.
d) Strings are very important to the feel and tone of your guitar. Old strings (which have rust, rough spots, dark areas) have been man-handled by swarms of people and the instruments in a big chain shop are not taken care of at all.. If the guitar sounds 'lifeless' and shows signs of any of those things above, ask them for a new set of strings or better yet, ask for it to be restrung before you purchase it.
6) After you have a guitar picked out, you'll want an amplifier as well. In the entry level price range, the sound isn't going to be awe-inspiring I can promise you that. In general, vacuum tube amplifiers will generally eat the shorts of any solid state amplifier but they are defently not cheap. Your first amp will most likely be solid state. I tend to tell people to avoid amps with onboard effects as they're generally terrible and you can do a lot better for under 50 bucks in a stomp box distortion pedal et al. The Roland Cube amp that Fritzo mentioned is a damn fine amp for the money and is perfect for beginners. It will give you reasonably good tone, portability and resale.
7) If you plan on using pedals, make sure you get enough cabling to accomodate.
Purchase a tuner when you buy the guitar. Inexpensive guitars typically don't use the best materials so your guitar probably wont keep tune very well. This is a cheap investment as well and keeps you sounding good consistantly.
8) And most importantly, PRACTICE! A lot of people get hung up in trying to get all these features and don't spend time learning. You WILL be frustrated up front and you will want to quit until you reach a significant breakthrough in your learning. This is very common and not meant as a deterrant but more a friendly warning. For me when I started, I would reach a point where I felt like I couldn't get out of a rut and then I'd figure something out that would make me rethink my entire technique! I suggest learning some of your favorite songs to the point of being able to nail them. A lot of technique can be picked up in this fashion. Play diverse styles of music and don't get to the point where it isn't fun anymore. If you get frustrated, put down your guitar and walk away for a while. Your fingers will callous up more as you continuie to practice daily and you will get faster and better. It depends on your level of commitment and if you have a natural talent for music.. as this makes it much easier to learn.
I think that should get you started, if you have any questions there are lots of guitar players on this board who can help you out. Let us know what kind of sound you're going for so we can suggest a guitar better suited for it. Have fun!