So sorry to hear what you are going though, it must be heartbreaking.
I have been the other side of the coin as I have carried a baby for a friend who kept miscarrying her own children (that was nearly 9 years ago I've since had 2 more for another friend who'd lost her womb to cancer).
Have you seen a specialist and had antibody tests done? Sometimes there is an immune issue that can be treated during the pregnancy although I don't know the details of what that involves.
In terms of costs, well they vary greatly. It is very rare for the NHS to fund surrogacy but some people have been able to get funding for the drugs needed for IVF and occasionally for the egg collection and fertilisation. The whole IVF cycle costs vary form clinic to clinic and depending on how you and your surrogate respond to the medications but it is upwards of £8k.
Surrogates receive expenses to cover things like childcare, loss of earnings, clothing, life insurance and other things depending on her situation. Legally these are meant to be below £10k but there are exceptions. If you have a friend or family member who is prepared to be your surrogate then usually these costs are lower but that varies wildly.
If surrogacy is something you really want to look into then there are a couple of big organisations that can offer initial advice and put you in contact with other people who have been through surrogacy or are also looking into it, that's usually the best place to start.
Sorry if this is too much information, I tend to blurt it all out, I know there is a lot to take in.
Again, I am so sorry to hear you are miscarrying.