I did the math and here's my solution: save up around 60k gralats. Dig or shroom or whatever for it. Use that 60k gralats on shovels. If I did my math right, you should use up all the shovels and have around or a little under 200k, all profit so you don't have to invest in new shovels. I think you have to dig around 3k shovels. Not sure though.