Hi so ive played D&D for 3 years now but i still dont know very much about the actual lore and characters from campaign settings. i dont really have the money to buy anything though. Is there a good way for me to get the info needed.

Well, the forgotten realms has a wiki, that has more than you could possibly want to know about the FR.

Forgotten Realms Wiki | Fandom

Beyond that, kind of a pet peeve of mine is to remember is there's not a "the" campaign setting. Lots and lots of us don't play in the FR. WoTC has released a number of different setting options in just this edition (eberron, Wildemount, and to an extent, Ravinca, Theros and Strixhaven.) People use old materials to play in setting that aren't published any more (Greyhawk, Dark Sun, Planescape, Spelljammer) And there are also lots of us who homebrew and might steal parts from a published setting, but would never actually use one.

The best way is actually to have a long talk with your DM about their world - it’s history, factions, locations your character should know of and about. If they tell you they are using one of the known worlds then you can find stuff about it online.

If your DM uses a homebrew world that they've put a lot of effort into I'm almost certain they'll be happy to tell you lots about it. Even holding back secrets related to possible campaign plots they'll very likely just love to geek out about their setting and the locations, nations, factions, history, etc that they've spent who knows how many hours thinking up. 

For official settings you can always do a web search for the specific setting, there's probably a wiki somewhere with lots of info if it's a long existing one.

For a DM most published or promoted lore should be consumed as inspirational, and maybe a little orientation if you're playing in a published setting as written.  

For a player, unless a DM tells you something is essential to understanding a PC or the game world, lore should just be regarded as entertainment.  There's no need to do it, unless the DM wants you to actively contribute to world building (in which case see my "For a DM" comment).  

Lore (whether published "canon" or home brew) can be tricky.  Game focus should be on the characters, lore can provide impetus for action or political parameters, but the intricacies should only go so far, and really go no further than matters that are directly shaping the characters lives at the moment or matters the PCs can have an impact upon.  Everything else runs the risk of turning the game into a book club where only one person, the DM, has likely read a complete copy of the book.  

As for specifics, I like Jorphdan's YouTube channel, does a great job collecting art from various editions, I believe his videos are largely Forgotten Realms focused but I think you'll get some more broadly applicable stuff when he's discussing Outer planar stuff.  MonarchsFactory is another great channel, and sort of does the opposite of Jorphdan's deep dives into specific canonical lore.  Rather, Dael Kingsmill has a really almost encyclopedic knowledge of real world myth and D&D lore and demonstrates, sometimes off the top of her head, that you too can easily build compelling mythologically compelling lore fairly easily.  Or at least she makes it look easy.  (She was recently a guest on DDB video, not sure what she was on for, but she's usually worth watching).  What I mean, is she's very good at demonstrating how understanding a game systems lore or a real world mythos can actually be an empowering tool to build your own lore.  Both channels have different but equally entertaining styles so would recommend both if you're just looking for stuff for your brain to soak up related to how D&D worlds have come to be.

Hello Morningstar36,

I strongly recommend some of my favorites for easily consumed lore. MrRhexx gives fantastically detailed coverage of lore for D&D. When I played a drow, his video on Eilistrade was vital to my understanding of drow who have escaped from Lolth’s clutches. The 12th level spell was also a really awesome video to watch. 

Runesmith is another YouTuber that I recommend if you find his type of humor enjoyable. He delivers his lore in a very basic, comedy-focused manner. In fact, his “Basically X” videos are appropriately named, but they are some of my favorites. Basically Kobolds is a good one to start with.

Jorphdan is also an informative resource that I would recommend. Here is his video on the lore of Waterdeep.

I think these are good ones to get you started.

AJ Pickett with the mighty glue stick channel I go to more than the others though they are good.  Check him out.