How much energy do you need if you only want to go to Orbit?

That depends on the mass of the vehicle you want to go into orbit. Lets say you have a Starship like the Enterprise weighing 4,500,000 metric tons. That's 4,500,000,000kg

Assuming it takes about 32,000,000 Joules of energy to get each 1kg into LEO and stay there, that means you need 144,000,000,000,000,000 Joules of energy to get into LEO

Antimatter provides 180,000,000,000,000 Joules per gram

Divide that by the amount of Joules the Starship needs to get into LEO and you only need ~800 grams of fuel.

Cost of antimatter currently is about $62.5 trillion per gram, so multiply that by about 800 and its about $50,000 trillion.

Of course, we don't need something as big as the Starship Enterprise just yet

If my calculations are off I don't care. It's convoluted and its 5am in the morning and I haven't had any sleep