Buy the biggest possible engine that a boat could use, power is never enough when you fish, we want to be able to get from one spot to another to explore. I was able to maximize my boat usage and skied on it with my children.
You also need:
1. To be mechanically inclined to fix minors issues on a used boat , otherwise you will get overcharge or gouge by unnecessary repair . Many mechanics cannot be trusted these days. With today's DIY youtube world and available resources, easier to fix anything these days then ever.
2. Lots of good deals across the US border or up north in buying anything used. Easy to bring them over here, and pay your duty taxes. Always ask the right question before you even show up, and you should test the boat before you buy one. Slow and non fishing season are always the best time to buy a boat. It is a buyers market in terms of buying a boat.
3. You need to consider storage , towing ability of your vehicle, and the needed maintenance.
4. Lots of accessories to acquire and add to a boat, electronics or down-rigging accessories can all add up to the cost of boating these days. Overnight hotel stay and food expenses are all added cost to a boat fishing trip.
5. Depending on your street smartness and being adventurous, boat fishing is not necessary more efficient then shore fishing, from financial and time usage perspective.