that "feature" totally sucks. I need to send small transactions to test my business logic. I would be willing to pay enough transaction fees to make the small transactions possible. this is the first time bitcoin developers have pissed me off with their changes.
protip: use
testnet for
tests 
+1
The minimum relay fee has always existed it was just set very low; so low that it allowed txs to be created that would cost more in fees to spend than the amount being sent. Unsurprisingly these txs tend to rarely be spent and unspent txs can't be pruned hence these tiny txs greatly contribute to blockchain bloat. Since the Bitcoin network is a shared resource some people would rather not relay these txs as they are uneconomical to spend and will likely just bloat the blockchain. Before the minrelayfee patch users who wanted to adjust relay fee rules would have to change the value in the source code and compile the program. Since the value of Bitcoin changes daily the minrelayfee needs to be adjusted often and requiring to recompile the program each time you want to do this is not practical. That's when this patch came in. The minrelayfee was changed from a compiled constant to an adjustable variable. At the time of the patches creation, 5400 Satoshis was the calculated minimum output that could be spent with a fee that would cost less than the output, so it was set as the default. You can freely adjust this by either starting Bitcoin with -minrelayfee=<minfee> or set minrelayfee=<minfee> in your conf file.
