Green is nice
You are asking a very variable question 1. What condition is the current finish, are you going to paint strip or sand blast. 2. How much rust does it have. 3. What paint are you going to use - there many different quality of two pack paints. 4. Will it be sprayed with clear over base or solid. What finish do you want vs what you are prepared to pay for - wet rubbed and polished or straight off the gun.
Having sprayed many motorcycles, cars and aircraft I can tell you its all about preparation which is expensive man hours, the actual spraying is only the last 5% of the job. Depending on the condition of your moke it could cost $3000 or much much more. The paint I have just put on my moke costs more than $200 per litre and that is just for the actual colour, not catylist, reducer, high build primer, etch primer, sealer etc etc.
So when comparing prices make sure you are comparing apples with apples . Stay away from el cheapo two pack for use in the Australian sun or what is referred to as a " Jam Coat " they just jam it on and push it out the door.
Hope this helps.