Well, first of all, you have to understand the different mining wais the topic is really long but is important to know that you can do mining with:
ascii miners, sha miners, video cards, hard disks... And the important question is 'Which are the coins who offer better profit?'. The answer is in the next service:
https://whattomine.com/It is hard for us to explain this topic in some words, It would be better if you give us a list of questions.
Ok well
1. i have 3 graphic cards of 1Gb each - can i have profit mining eth?
2. i know that i need to buy new hardware, but i dont have to much money - What should i buy? i have like 100$ to invest
3. When can i see profit?
4. Wich platform is the best to star? a pool or maybe by my own?
5. Can you help choose a hardware low cost to start maybe with ETH o Dash
6. Sorry my english is not so good but i want to know with the best in this foro and the spanish forum is not so helpfull... heheeh
Thanks for all!