Bump that budget up to $300 to $400 and get yourself a decent to great bike at danscomp.com
But what kind of riding are you wanting to do?
Street,Park/Vert bmx frames pretty much have the same or similar geometry about them...toptubes around 20" to 20.8",chainstays 13.25" to 14".Dirt Jump bmx frames are similar but usually with longer toptubes (20.8" to 21.75"),13.5" to 14.5" chainstays,and a longer wheelbase.
You can use a street bmx for park/vert or dirt jumps/trails...you can use a park/vert bmx for street or dirt jumps/trails....you can use a dirt jump/trails bmx for street or park/vert.
Flatland bikes have a geometry all their own with short toptubes measuring 18" to 19" (a few companies offer 19.25" to 19.75" frames for the taller guys),short chainstays around 12.5" to 13",more clearance for your feet between the downtube and front wheel to make scuffing tricks like squeakers easier,lower slung toptube to make stepping over the frame in tricks like whiplashes easier,steep head tube angles to make whipping the frame around easier.
I would not recommend riding anyting but flatland on a flatland specific bike as they are not designed to take the abuse that street,park/vert,and dirt jump/trails bmx bikes take and you will damage or break the frame and parts.
If you really wanted to ride flatland with some light street you could purchase a Hoffman Strowler which is a flatland specific frame but made tough and for some light street (it is Kevin Jones' signature model after all) and build it up with some tougher street parts but building a custom complete is expensive (upwards of $1000).
Get back to us with what kind of riding you plan on doing and we can suggest some decent bikes.
The only decent bike near your price range that I can think of off the top of my head is a DK Cygnus wich retails at danscomp.com for $279.99 before shipping.The DK Cygnus is a Park/trail designed frame with a 20.5" toptube,has a chromoly main frame (way better then hi-tensile steel,and lighter/stronger).
When buying a new bmx that you want to be both strong and light it is important to get a frame made from 100% chromoly tubing or at the very least a chromoly main frame (toptube,downtube,seat tube,head tube are chromoly) as chromoly tubing is stronger and lighter the hi-tensile steel tubing of the same thickness and diameter.