Hi and Welcome to the forum.
Fiancee visa is cheaper initially but more expensive in the long run. Overall it is much cheaper to marry in the Philippines and then apply for a spousal (Settlement) visa.
You would need to sponsor her visit, but although things have been easier lately, it's still not easy to get a visit visa. One thing is for sure, you'll have to have gone to the Philippines and met her to have any chance of success. The sticking point when it comes to ECO's (Entry Clearance Officers) deciding whether to give someone a visitor visa is the likelihood that they will return to the Philippines before their visa expires. They tend to have a very narrow view of thing - she comes from a very poor third world country, once she's been to the UK, why would she want to go back there...... They want to see evidence showing compelling reasons why she would and to them that usually means a good job, property and money in the bank.
Apart from times like Christmas and the main UK school holidays, you can usually get a return flight from between £400 and £500, sometimes even cheaper than that. You can get an acceptable hotel room with aircon for around £20 to £30 if you get their phone number online and call them direct. Even better than that, you could get your girl to book somewhere nice for you because there is nearly always a premium to pay when the locals are dealing with a foriegner..... in Phils it's called the Kano tax.
Cheers,
Iain.