Hello-thanks for the invite! I think it’s great that you are looking to continue in the sport of bike riding. I think you did right by getting a cheap bike to try out the sport. I always recommend this to people looking to start bike riding for the first time. It’s not for everyone, so if a person does not like it, they are not out all that much. I feel Craigslist is would be your first best source for a new bike. You can find a top quality bike for a bargain price (sometimes from those that bought an expensive bike first and found out they didn’t like it lol). Ebay is good too. There will be almost infinite choices and you can find your size easier than CL, but you will not be able to see the bike before purchase, unless it's a local seller. Also, in most cases you have to pay shipping too, which some charge as much as $100.00 to ship.

I want to mention three types of bikes that I think would work for you. Mountain bike or MTB also known as Cross Country (XC), a Cyclocross bike (CX) also known as a Gravel bike, and a Hybrid bike. The MTB bikes are going to be the most common ones on CL & EBay and the best bargains can be found with a MTB out of the three types. If you know or you will not be riding on technical trails and rough trails (or not very often) I would recommend a hard tail MTB. Less maintenance and less cost. Mountain Bikes are also the strongest of the three I mentioned. The next bike is the Cyclocross bike. This bike is like a road bike that you can ride both on and off road. It would not be a good choice for a really rough trail, but is great for easy single track trails and dirt roads, plus some mud, cuz mud is always fun!! It's also good if you want to really burn some calories, and do some longer distance (relative to you that is) road riding. The last bike is the Hybrid bike. Mostly intended for paved road/trail use, but can be taken off road as well on light trails. With a Hybrid you will be in a more upright position than the other two and is more of a "Leisurely" type of riding. I think all three would be good to go with your weight and weight goals.

One of the most important things to consider when choosing a bike, is to get a bike that “Fits” you. The best way to know this is to go to your Local Bike Shop (LBS) and get measured. This will set you back about $100 plus or minus a few bucks. There is also plenty on the internet on the subject on how to find out your bike size at home. In any case it is imperative to get the bike that will fit you. It can make or break you on your riding experience.

You didn’t mention your budget, but I would think for $300 to $500 you would be able to find a really nice bike in any of the three categories I mentioned above. When you find a bike post back and let us know, or if you find one and want to ask about it before you purchase post it here. Hope this helps a bit.

One point that I would like to add is don't get cheap wheels. Someone of your weight (I now, I used to be 260 for a while) needs really strong & stiff wheels. Leave the low spoke count light-weight stuff to the little guys. Make sure that you get deep section rims with 32 count 3 cross laced spokes and you will be a happy camper. You won't be busting up wheels anymore and your bike will not feel like a wimpy pretzel when you ride it hard. Also, forget the skinny tire nonsense. Ride on at least 28s, if not 32s. Again no more pinch flats and much more comfortable.

Your already part of this group ignore my ignorance please !
lol

Another thing to keep in mind is gearing. You'll find riding much more enjoyable if you get a really good cassette (11-36) on the back, and a good crank (44-33-22) on the front. Having the low gears to spin up hills will allow you to build endurance, and keep you from injuring yourself. I'm still above your weight and I average about 12 MPH and have ridden 17,000 miles in the last 3.5 years, and I could not have done it without great wheels, and low gearing...

I by no means am an expert on cycling. But I was 306 when I started this year. On top of all the excellent tips you have been given I will just add the following.

Budget is everything. If your looking to spend little find yourself a rigid fork hard tale MTB. Most suspension forks are not meant for us Clydesdales especially on the cheaper bikes. And rear suspension on a cheaper bike is pretty not meant for anyone. As you go up in price then you start to get forks that will take the extra weight same goes for rear suspension.

I bought a used 2003 Trek Liquid 20 at the start of the summer. The phsylo forks were just to soft and because of the age replacement springs were impossible to find. So I sold it to some skinny dude and bought a Used 2009 Trek Fuel EX8. It has air suspension which allows me to set the fork pressure using a pump and has a lock out so when on roads or climbing I can just lock the front out. The difference is night at day. I love my Fuel and look forward to every ride.

You can do that!

If the chain jams when you pedal backwards, it is probably the rear mech not quite being in like with the cog on the back. Does your bike have index gearing (little numbers on the shifters).