Reptile expo coming up?

so in june there will be a reptile expo in san diego and i want to know what will they have and whos going... i am trying to sell my ball python so i can have some money to buy another snake or lizard but i dont know if i should get a breeding pair of leopard geckos so i can breed or a boa or somthing... i would only have like a $150 budget so what do you think.... could i get a breeding pair of leopard geckos and buy an incubator? are leopard geckos cool pets to have.. do they come out much in the day.. what snakes could i get besides a ball python and a cornsnake that could fit in a 55 gallon tank??