I got a dedicated pallet buster and it makes life so much easier, it's about 30 quid but well worth the investment if you get hooked on pallets.
Roughneck ROU64644 Sturdy Pallet Buster https://www.amazon.co.uk/dp/B0742HVH2Y/ref=cm_sw_r_apan_i_01E7J1QV4025V17T8YQ5?_encoding=UTF8&psc=1
Just a heads up: We needed pallets for our company and our supplier isn't taking new customers. You may be able to sell some and buy your tools with the $$.
If I was getting into pallet breaking on a more serious note, I'd explore the pallet buster/pry bar thingy as well as that pneumatic nail driver that I've seen on this forum.
cat's paw, aka moulding pry bar
You can use it with a mallet or hammer, but I've never needed to. I'm pretty sure I picked a couple of them up from HD or Lowe's for $8-12 or so.
They work like a dream.
I have this one and no issues with it. I have had some tough boards too and it pulled them, some that I was probably better off dumping.
https://www.amazon.com/Roughneck-ROU64640-Demolition-Lifting-Bar/dp/B003CT4D1S/
Never saw the nail puller that is amazon recommended with it, but I bought mine on amazon UK, no nail pullers there.
I have this (http://www.amazon.com/Vestil-SKB-DLX-Deluxe-Pallet-Buster/dp/B00JH41U7M). I bought it straight from the manufacturer a couple years ago. It is the most efficient method of disassembling pallets. I have tried every other method that can be found online and this works the best. It can take apart a pallet in 10 minutes, more if you are being super careful. Time is valuable and some methods of taking pallets apart can be rather dangerous.