I'll share my experience with Weber gassers.
A few months ago I responded to an ad for one asking $40. No cover, no tank, needed a grate and flavorizer bars. I offered $30 and the seller took it. It is a '00 Genesis Silver A and was otherwise in pretty good shape. Someone on this board pointed out a CL ad for someone selling Stainless flavorizer bars for a Silver B out East. They agreed to ship and for $31 I had a set of SS bars. A few minutes with an angle grinder and cutoff wheel and they fit.
It turns out that some really nice CI grates which were on our property when we moved in in '87 fit well enough. I picked up a propane tank (on CL) for $15 and spent $20 to refill it. In a weak moment I called Weber and bought the official cover for $40. (They comped shipping.) It cleaned up real nice and I'm really happy with the results I get with it.
A month or so later I replied to an ad for a free Weber gasser on CL. What I found was an '01 Genesis Silver B. I felt like I had found the big brother for my Silver A. It came with a tank (out of date) and a cover (funny enough - didn't fit the 'B' but it is the right size for my 'A'.) Best part about it is that it had already been upgraded with SS grates and flavorizer bars. All it needed was a good cleaning and a cover that fits. I even lucked out at the propane dealer. I asked them specifically if the tank could be refilled and they didn't notice the expired date until after they had done so. For the cost of a propane refill and some elbow grease I had a working grill. Well... It does need a thermometer to be complete.
A few weekends ago my son called after he had left our house to tell me about a Weber out by the curb a few blocks away from home. I checked it out and found what looked like a serviceable Genesis 1000 with the older quick connect regulator. It looked like it had the porcelain coated grates and flavorizer bars. It also had a ratty shorty cover on it. I hemmed and hawed for a minute and then passed on it mostly because the of the regulator. Later I found that Weber sells a modern regulator and hose for $30.
I've seen some other awesome deals on CL. (Or maybe just someone fishing for email addresses.) But I have what I need. I still watch just in case something special comes along, like a gasser with a side burner for real cheap.
There's plenty of discussion on gas vs. charcoal. Tonight I used my small gasser to grill some eggplant for a salad. Later I fired up a kettle to roast some corn and grill some salmon, onions and a pepper to complete dinner. Horses for courses. The gasser is incredibly convenient for grilling a few veggies. Charcoal is great for meat and fish and stuff that takes a little more than a couple minutes on the grill.
My recommendations:
Look for other sources for parts. Someone just listed flavorizer bars (unused) for a Genesis 300 series for $15. Also see what you can find on eBay and search the Internet for other parts vendors. Weber is probably going to be your most expensive source for parts.
Take your time and wait for a special deal. I've been surprised how often some good deals show up. It helps to have something like an iPhone or Android app to help watch.
Edit: I forgot to add that I found an unused rotisserie that fits both of my gassers on CL for $5.
I wish you luck finding a gasser that meets your needs at a price that makes you happy.