Ebay for sure...but the competition is stiff currently ;) I've just found a lovely maternity H&M wool coat on there and the seller was local so I managed to save hugely on P&P as well as getting a fab quality coat for a fraction of what it cost new. Hope you find something suitable!
Tesco are doing a swing coat for £20 that might do in a bigger size. Have only seen it in the paper so far but seems to only fasten at the tope which would allow your bump to poke through towards the end.
I bought the tesco swing coat. I'm 37 wks and there is loads of room in it still. It does have 2 more hidden buttons so your bump doesn't have to be cold. Also has a small stich in the back at the hem which if it didn't quite fit round your bump you could unpick.
I tried it on before looking at the price and was really surprised it was so cheap. It doesn't feel cheap!It cost me £25.
I only had to go one size bigger than my non pregnant size.
I too have bought the navy military one from Red Herring which was about £60 but looks really trendy and not too 'maternityish' - I just need to source some decent over the bump jeans that won't fall down !
I've just bought one from UniQlo which is nice and has buttons to just under the boobs so plenty of room for a bump to grow and still be warm - I rolled up a big jumper and shoved it under just to make sure! They have black, grey, red and purple.
when are you due? If not going to need it over the full winter then possibly try a woollen wrap/cape. i find I am not so cold when pregnant anyway and these are good as warm enough and then handy when feeding post birth.
I had the long fleece coat from JoJoMaman last time and it was great - it is still alive for this pregnancy with no.3 having done the rounds with several friends meanwhile. Just get it in a practical colour and not cream like me (doh).
O.M.G . . I had a nightmare trying to get a maternity coat, wanted one that covered my bum and thighs and was quite smart rather than parka style. Ended up getting a non maternity coat in George at ASDA for £35!! Am normally a size 10/12 but got it in a size 14 and its perfect!