How to start using IDL in 2015? Unfortunately it looks like I have to run a bit of old astronomy software on IDL. I keep running into statements that "I need to buy a license" in order to run IDL. 
Is this true? 
How can I download this software and begin using it? 
 A: DON'T. Yes, using IDL requires a valid license.


*

*If the code can be re-implemented in Python in a reasonable amount of time$^1$, do it. You might be helped along by astropy and pydl. The former provides a growing library of useful astronomy functions, the latter specifically targets reproducing astronomy IDL routines in Python (and is affiliated with astropy). I don't have much experience with the packages myself, but I hear mostly good things. There are many reasons that IDL will drive you crazy and waste your time (of course python or any other language will too, but less).

*If your code is short (in terms of runtime) you may be able to run on an unlicensed version of IDL. Last I checked, the main restriction on unlicensed status was a short runtime limit (7 minutes?). There may be other restrictions, I'm not sure.

*As Chris White pointed out in the comments, most astronomy departments (or member of said departments) have some IDL licenses floating around that you may be able to make use of.

*If you decide you must buy a license, last I checked (3-4 years ago?) student licenses were substantially more affordable than standard licenses, I think it was 1 year for ~$80.

*Getting into some speculation here, but some older versions of IDL may be cheaper or "easier" to obtain.
If you can 
$^1$Reasonable amount of time being a fuzzy concept. If you just need a quick use of one routine and then never need it again, probably not worth spending too much time. If you'll be using the code for the next 3 years, it's worth spending 2 months porting it. If in addition many other people will want to use the routine, all the more reason to spend the time (and contribute it to astropy, if appropriate). See also: https://xkcd.com/1205/.
