If you are in a poor country with a weak economy you could also benefit from joining a signature campaign. You won't be able to do it for about a 2-3 month period where you must show your contribution to the forums, but honestly that will probably end up earning you a lot more than mining with a single computer and you would also learn a lot more about crypto in general. Check the local boards if you speak a language other than English and you might be able to help there as well. Good luck.