A CP386 IV37 Blastoise with terrible moveset

I candied the blastoise that I caught. I only caught it in the hope that it would have a more decent move set than the blastoises I evolved, though.

I think you answered your own question... I'm at the point where I evolve Squirtle for XP and no longer evolve Wartortles... Too expensive in candy for a really mediocre all-around mon. I haven't used Blastoise at all since September after the "coolness" factor wore off.

It depends on how big your mon bag is and how sentimental you are.
I still have the 1st mon I caught. It is totally useless but I'm going to keep it forever. My mon bag is still the default 250 but there will always be room for my 1st mon.

Blastoise has no bad moveset. The worse one Bite/
Flash Cannon is pretty usable. Honestly running into one of those is pretty exciting for me. I've only seen and caught 1 Blastoise and evolved 2 more. I love starter final evolutions which are borderline legendary Pokémon in my mind. I'd rather run into them than the swarm of Abras/ Kadabras/ Sand Shrew/ Slash and usual junk around my block lol. Still seeking a Watergun/ Ice Beam Blastoise to terrorize Dragonite with.

I've evolved one (water/flash) that I'll use as an occasional defender (yes there are better but he'll do an okay job).

I use a low cp (1000 ish caught water/hydro for prestiging and have a lower one that I've yet to find a use for but haven't ditched.

I have a small army of Bite/Ice Beam Blastoises which I evolved and felt upset with. At first I thought they were totally useless, but later I discovered they are amazing prestige mons versus Dragonite. I can now say I use them daily and prefer them to a Water Gun/Hydro Pump Blastoise which would literally be a weaker version of Vaporeon. At least this "bad" moveset has a niche to fill.

You actually answered your own question. I have a perfect IV Blastoise with Water Gun/Hydro Pump. I pumped him up to cp2079. One of my fave mons. and perfect IV - still useless. I love it, but there's just better mons to do what he does (other than look cool).

You're going to get 1 candy for transferring him. Squirtle candy at that...not really that hard to come by. So if you want to keep him for fun, you're giving one candy and one spot in your poke bag. If you can afford that, then stop lamenting and just keep it - regardless of the fact that it's useless. If you would rather have 1 squirtle candy and one more spot in your poke bag - transfer him. It's really not a tough choice. And hardly worth asking someone you don't know on here what to do with it. Right?

Keep...He's your first Blastoise :3