I didn't increase my strength, so my weight limit is at 200. I was wondering if I should sell my flamer or mini gun or even my fission batteries. I don't use big guns, mostly small guns.

Of course! Either sell what you will never use or get a player home and store it. If you've aquired a follower they can carry your fission batteries and your big guns, just don't give them the correlating ammo. My character is a collector of sorts so she is always traipsing towards home to store her new found stuff (and sometimes junk).

I cant exactly afford a follower and is getting a home simple?

Welcome to the forums!.. and the game?

Check the "misc" menu on your Pip-Boy for anything useless such as cups, plates, wrenches ect. And if you're not going to be using your big guns then sell them.
Getting a home is quite simple; the bomb in Megaton. That's all I'm saying.

200 carry limit should be plenty for Fallout 3. My recommendation is to just sell everything you don't need.

What kieranbhoy said was right. Hang around Megaton for a while, and you'll get a quest that will lead you to either of the two housing options available depending on your choices. And if you want to free up weight in the mean time, selling your guns would be okay because I'm sure you'll come across some more out in the wasteland.

Storeing Items in containers safely , isn't contained to only official houseing.

Alright, thanks guys! I sold my flamer and I am currently doing the quest to getting the Megaton home. I just need to level up one more time so I can get the required explosives skill.

You don't have to have the Megaton home. There are plenty of other great places to hide out in and store your stuff.

You won't need explosives skill to disarm the bomb. Use Mentats, and you should be able to disarm the bomb.

Personally, I think the mini is way overrated. The thing is slow and unless it's in perfect health, half the rounds just spray all over the place. Definitely not worth the weight. I used it one time when I was just going to burst into a building and spray everybody. That was it. I think it works best if you collect all the weapons and keep them in a state of good health, but just store them at home and pick the ones appropriate for each trip you make. You definitely want to leave home with plenty of room to carry stuff. I only carry one long gun, one assault, one close-quarters and one side arm.