If you want to get more money and if you want to get money faster, then I would go with digging. I would go with digging because each hour you can get a lot of shells. You can get between 500-1000 shells each hour by digging. This means that you can get between 1500$-3000$ if you sell all the shells you get each hour. That is my opinion, although I know a lot of people have different thoughts. So not everyone would agree with me. Probably many people would say making pizzas or doing car missions. These jobs are very good too but I would go with digging.