Well, I beat it for the first time today. All through the first two areas, I was saving my money, hoping only to give the tunnel dude a fat wad of cash and hopefully get close to opening up the last shortcut. By not buying any items, I did manage to save up just over a hundred thousand dollars by the time I cleared the ice level. However, it was a great run even with me being a cheapskate. I got five saves, and found several crates such that by the time I got to the jungle, I had twelve of both ropes and sticky bombs, and a SHOTGUN, the first legit shotgun I ever owned. Sadly, my precious shotgun fell into the endless void while I was on the first ice level.
Other than the spike boots I got off the Giant Yeti, and the glasses I got from Kali's Altar (sweet Armok, I love those altars when I get a chance to use them), I didn't own a single item.
Then once I got to the Temple levels, I managed to use a sticky bomb (and the terrain) to persuade a Mummy Lord to share his scepter with me. That made the rest of the game a joke. Thanks to the advice I received on here, I knew to treat the final boss like SMB3 Bowser, and thanks to the scepter, the enemies he spawned served only to give me a gold trophy for kills.
My final scores: Money: 108775, Kills 125, Saves 5, Time 30:42, Deaths 111, Wins 1.