I learned to sew on a White Rotary, like this except treadle, and it is a good machine. You can find bobbins occasionally on Ebay. They are not as deep as Singer bobbins and are larger in diameter. A dear lady on QB sent me 2 that she couldn't use in her machines. They don't wear out and while rather inexpensive, the price is steadily rising because people like them and they are pretty. The hand wheel turns away, rather than toward you, which is a little different. Use lots of solvent and oil on the stuck parts and you will eventually succeed. Good luck.
Donna