i have a schecter sgr c-1 and a line 6 15w amp.
I want to learn songs by pink floyd and im particularly looking for a sound like the guitar in the dark side of the moon, or as close as i can get with my gear. my amp has basic gain controls, effects like flangers, phasers, chorus, reverb, etc. but i am looking to get my first pedal or two and don't know what i should get first. which are important for solo's (solo in time, what effects were used? chorus and distortion or overdrive? whats the difference?). I was thinking about getting either a chorus, overdrive, or possibly a boost pedal. please let me know what you think. im looking to spend between 50 to 200 dollars (higher end being two pedals unless it really is worth it for me)

I know it's a lot of questions, but there's so much i don't know yet about pedals. I am looking for:
-which pedal(s) will be most useful/necessary to get first
-any information on effects pink floyd uses often
-difference between distortion/overdrive and which is what i'm looking for
-recommendations of certain pedals/brands

Any tips or advice is greatly appreciated, thanks!