Hope I'm not repeating advice given elsewhere, as haven't read the whole thread. Rose essential oil is indeed extremely expensive - I paid £64 for 10mls a while ago, and that was cheap. You could try a mixture of Ylang Ylang and Geranium for a very vaguely similar smell, but nothing will smell like rose except rose.
Do bear in mind that the amount to use of essential oil would be max 2%, 1% would probably be enough for rose, as it is strong.
If you go for the more affordable alternatives like Ylang/geranium why not experiment with a cheap bar of rubbish from Wilkinsons first, in case you waste you're shaving soap - that way you can at least test the smell.
But do bear in mind that essential oils are highly concentrated, and can be irritating/sensitising. Lavender is a good one to start with, or tea tree if you like it, as these are the least likely to do you any damage.