Just about all Programming languages are free to use...
and those IDEs that require purchasing can usually be gotten for free anyway... (leagally)
for instance Microsoft make Visual Basic, you have to buy a license, BUT... MS arn't stupid.. they realise that it makes the language inaccessible to new developers wishing to learn... no new developers = no new sales... hence even the most expensive IDEs out there (arguably MS) have free to use versions labs.msdn.com for the latest MS developing tools including Microsoft SQL servers etc (few thousand ££s per license).
BASIC or PYTHON are the easiest though, i would suggest python, because if you get good with it, then it has socket programming, so you can make web programs easy...