General Cycling Discussion - Looking for a little help here...new rider

First off... Hello there. I might as well just let you all know my situation. I'm looking for a simple hybrid bike (I want to be able to ride in the city [Chicago] and be able to do some trail riding as well) or the like. I'm quite new to bikes I guess. I used to love them as a kid...then I got my drivers license. So any help is appreciated on my questions. First, is $100 a decent price for a Specialized Hardrock GSX? I'm not sure on the year or the condition its in...waiting for pictures but I thought I would ask anyway. Also, what are some bikes that I should be looking at? My budget is $100 give or take some. I honestly DONT want a bike that will cost me more money. Being in the city I'm aware bike theft is a problem even if I have a lock. So I'm just wondering if anybody knows what kind of bikes usually go for around that price used.

Sorry if this question gets asked a lot. Thank you for your help!

The Hardrock is Specialized' lower-end MTB and I would expect to sell one for 100 dollars if it were in decent-but-worn condition. I think they go for under 400.00 brand-new.
Note that the Hardrock is not a "hybrid", it is a mountain bike. It will come with knobby tires and will not be the best for street riding which is likely what you'll do most.

Here's the problem. You say you're "new" to bikes and yet you want to go out and buy a used machine. If you don't know what you're looking for, you may be throwing away your 100.00.
Do you have a friend who's knowledgeable? If so, take him along when yo look at the bike. See if it has any major problems or needs repairs or replaced parts.

The Hardrock may well work for your needs..... Easiest thing to do is toss the knobby tires and buy some street tires for it. Nashbar usually has some on sale for about 10 bucks each. Then, it'll be much easier to ride on the street, and will still handle light off-road riding on improved trails.

Go to your local bike shop (LBS) and check out different models. Get an idea as to what kind of bike works for you. If you're not that familiar with bikes in general, it might be more beneficial to buy a bike from your LBS to get support and maintenance if you have any problems.

The most important thing about getting any bike is to make sure that it fits you. A great bike for $100 is no good if it is too big/small for you.

Thanks for the advice. Found another possible deal: Trek Antelope for $120. From what I researched this seems more like a hybrid bike...better for my needs. I'll be checking it out after I hit up a bike shop on the way (same town). Any red flags I should look for when checking out this bike?

Yes, the "Antelope" is a hybrid, and a fairly decent one. I'm currently rebuilding one now. On older bikes like this...."wear" items can be an issue. Check the headset bearings; the headset should move freely with no "crunch" when you apply twisting pressure to the front end.
The only real way to check the state of the wheel and bottom bracket bearings is to take the wheels off the bike and/or remove the cranks....Not practical. Just make sure the wheels spin freely and true, and the crank does not have any excess play.
Make sure the shifters work accurately through all the gears and check tire wear. That sounds like a reasonable price for a bike of that type if in decent condition; it's about what I'd charge.

Thanks for the help it has come in handy; I thought I found a deal and it turned out the bike was crap. Missed a few other deals but that is the beauty of craigslist. Hopefully i can grab my next deal: Trek 820 for 140 (or best offer yay!). Thanks again