i've been playing drums now for 9 years. Originally inspired by my Grandad as he did marching, jazz and blues. So i kept this on for him to make him proud especially with me now doing a degree in music.
For rock/starter stuff.. I know music theory is a pain to read but it really is worth reading/looking into. Ill admit its my main weakness but i still try lol. Trust me learning to read from music will help for anything in future. I class myself as a more "ears on" drummer where if a bass player starts playing a line/melody i find it very relaxing and creative to play along with the groove and use my creativity to go along.
I know its not free but it is really worth buying for only £10. Go to a local music shop and look for a book called " Practical Percussion by Kevin Edwards" This book helped out quite a lot for when i was learning rock beats and fills etc. With that book it can help you learn what types/styles of beats there is out there!
Its also worth watching a lot of online drum lesson videos on youtube that helped me quite a lot and even going to live drum clinics etc..
Hope this helps
Andy x