You will not go wrong with an Orkney Longliner if this is your first boat. You should be able to pick a good one up, with an engine and trailer, quite cheaply. Have a look on the website
http://fishingboats.apolloduck.ie/
If you have some more cash to spare then you could try an Orkney Strikeliner. If you want speed then you will have to move up to a Seajeep or such like boat. I just sold my Raider 16 Fisherman and have traded up to a Raider 18. You will not get a better boat. However, I have worked my way up to buying this over 20 years.
Do remember the main aspect is safety. Don't buy a cheap boat that may be unsuitable for the sea.
Secondly, if you do not know anything about engines get someone to check it out. You will not go far wrong with any Japanese model.
Finally, if you are launching on your own then you will need a trailer that facilitates you doing this.
If I can be of any more help just pm me.