New to classical music

I buy most of my classical from three sources:

Presto Classical | Buy classical & opera CDs, DVDs & Blu-rays online

Classical Music | Your source for hard-to-find classical music recordings - ArkivMusic

Berkshire Record Outlet – The Classical Choice for Collectors

I think you are smart to build a collection on CD. The prices are really low for used these days and you can go to a place like Princeton Record Exchange or shop online and find tons of inventory for minimal dollars. I have found several European labels (Archive, Hyperion, Accent, Alia Vox) that offer consistently good sound and performances and these can usually be had for under $5. Have fun!

If you have a SACD player then go for those as well which can also be had pretty cheap and usually have better sound quality than Redbook CDs.

My take. Buy CDs after you've listened to lots on Tidal. I have been listening to classical music for over 70 years (not a typo). Grew up with it. Google "Gramophone best recordings of".... Beethoven, Chopin, Rachmaninoff, Dvorak and Bach as a starting point. Listen on Tidal to those specific recommendations and let your tastes grow from there. You have a lifetime of enjoyment ahead of you. I am still constantly hearing things I have never heard before. The website "Talking Classical" has amazing lists of the best and most important pieces listed by type once you know what you really like. Be sure to check it out as well. Have fun. An amazing journey awaits.

Edvard Grieg has been mentioned in passing, but specifically, try "Peer Gynt".  Lots of drama in there, and you will recognize a few of the melodies from movie soundtracks, tv commercials, etc.  Make sure to get a full orchestral version since there are other versions (e.g., solo piano, etc.) that wont' give the full effect.