In addition to safety stuff and warm clothes, here's what I'd get to avoid breaking the bank:
Ice fishing rod and reel - $10-$25
They have some decent rods for cheap at GM.
Cajun Red Line - $4
This is my favorite monofil.
Bucket - $5?
Great to haul stuff in and great to sit on.
Tipup - $10-$18
Why not have another pole in the water to increase your chances for success?
Tipup line - $5
Small Tackle Box - $10
Tube jigs - $8 These seem to work well on all trout. To save money now, buy them as you need them. For example, if you are fishing Tarryall this weekend, buy micro and small orange or charteuse tube jigs and a pack of meal worms.
Ice scoop - $7? I forget what they cost, but when it gets cold and your holes start freezing over, you'll be glad you bought one.
Hand auger - $70
Walmart sled - $8
They work ok for hauling your stuff across the ice
Can cooler - $1
Nothing worse then grabbing an ice cold beer with ungloved hand ;D
Total - $138
I spend half of this on gas in a weekend.
Total with 10% GM discount - $125.00
I'm sure there are some other great suggestions from other folks on this board!