How can i stock my 35 gallon aquarium?

ok right now i have 3 koi and 2 goldfish in the 35 gallon. im going to give them awa. would i need to cycle the tank again if i put tropical fish?i want neon tetras,guppies,platies,ghost shrimp. i dont know more fish that are compatible but if theres room left can i add more?how many fiish will i need?will i need to cycle the tank again?if im missing more information please tell me.i would also like more info like taking care of them.thankyou.O and one more thing, how much do you think it would cost me for everything?