It's so weird to not be able to recommend Prince Albert or Carter Hall to a beginner anymore. What has the world come to?
I've smoked Spirit in a pipe when I first started. Beautiful RYO, but burns hot, sharp and acidic in a pipe. Bugler is surprisingly much better, and some "pipe cut" ryo isn't altogether terrible, but as far as natural tobacco goes, you can't beat a good Flake or Ready Rubbed pipe tobacco.
Honestly tho, try some Sir Walter Raleigh, possibly the last OG OTC standing. Unless you hate licorice.. it's still available in grocery stores around here.
You can get your feet wet with crossovers like Revelation Match/Epiphany (remakes of Einstein's fav), Lane HGL, or Sutliff Aromatic English.
...Or dive into the deep end with a classic English blend like Standard Mixture, My Mixture 965, or Early Morning Pipe.
*Also, consider perusing the monthly What Are You Smoking threads to see what all the heavy smokers are keeping in rotation. Constant inspiration for P/TAD.