To fix BMX handlebars, you might need to bend the handlebars back to their correct position. You might also need to tighten the bolt that anchors the handlebars to the bike. Fixes will vary depending on what is wrong with the bike.
Tighten the stem
There are a few places where one can purchase a BMX cruiser. This includes going to a BMX bike store, as well as looking at cruisers online on sites such as eBay.
If one were to purchase a freestyle BMX bike, one could go to a specialist bike shop. Alternatively, various specialist companies, such as Vital BMX offer a huge range of products.
You would be able to purchase a BMX frame from a retailer that sells BMX bikes. You could probably even find some used/old ones from craigslist or ebay.
Carbon handlebars are a rarity when it comes to handlebars. The best place to look for those would be special ordered from a local magazine company. You may also want to check a local bike parts servicing area.
One may purchase Haro BMX bikes from Sport Chalet. They offer a wide variety of colors and styles to fit any taste and budget. Accessories are also sold at Sport Chalet.
The BMX bike stems are used just like any other bike stems for most any brand. The stems hold together the base of the bike and the steering part or the handlebars.
One can purchase a 24 inch BMX bike from Amazon and the Bicycle Warehouse website has a buyers guide on choosing the right bike for ones needs. Amazon has a 24 inch BMX Diamondback Nitrus on sale for $299.99 in red with DB sound alloy platform pedals.
purchase a new set
No. Grips and handlebars are fairly well standardized, so pretty much any grip will fit.
The most obvious places to purchase a used Fit BMX bike would be from online auction sites, such as eBay. There are a small number of online retailers specialize in secondhand bikes, such as LocalBikeTrader.