Hello... Ive been digging for samples on vinyl since the 90s, but of course as technology advances Ive scoured the internet for samples, but I still very much dig for vinyl and search that way too still!...
My advice for those starting now is use both ways... I wouldnt recommend searching for 'hip hop samples' online... If you want to find unique obscure stuff then search Jazz or Funk/Soul forums or reddit pages or youtube channels NOT made for sample heads. Listen to those people who love those genres... find out who the greats are and the members of their bands who maybe moved on to other bands... If you do look for vinyl, then ask the record store owner. Dont ask him for good samples, but ask for any 60s/70s music that has heavy drums... or violin... or piano, etc... whatever youre into. theyre usually helpful and will point you in the right direction.
At first its VERY daunting and can be overwhelming bcos there is just soooo much music to dig for... but the more you do it the more you will understand where to search and how to and not waste as much time... BUT, you have to begin somewhere and you WILL make mistakes! I wasted tons of money early on buying records that were useless, but that forced me to learn more.
Also, a good website to look is 'whosampled.com'... obviously this is a site of samples that have already been used, but will give you a good idea of what types of artists to look out for, what year, era, genres, etc
PEACE