You can use this to spam txs, it uses Nickel, a set of tools written in python to interact directly with NIS. I have only used this on Linux and it might need some libs installed, just run it and if any errors install missing libs.
Download Nickel:
http://s000.tinyupload.com/index.php?file_id=33119505436068887222In the folder there is a script called nickel, just add the private key for the account from which you are spamming from and put in the address of the account to where the spam is going, ie:
python ./nickel.py send 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef NBCNGAGUEGFBY2SUV4Z66ZSOENJ4GGBF52J3DI6N 8000000
The 8000000 means 8 XEM will be sent.
The fee for txs is set in NemConnect.py and it is set for 2 XEM, it can be changed if you like.
Create two wallets, put some XEM in one of them and spam to the other wallet, when first wallet is empty then spam from the second wallet back to the first wallet. Repeat. You will only be losing 2 XEM a txs so it is pretty cheap.
If your computer can't handle the 1 sec txs speed it can be changed in the nickel script.
Edit:node must be BOOTED to execute any nickel commands
Edit #2: If you have a wallet with a good POI score then make sure you are harvesting from that wallet but don't spam from it, you might be able to recover your txs fees from harvesting.