I think it depends if you are needing everything from scratch, and how DIY and low tech you are prepared to go.
I've read of people using mango chutney barrels modified by fitting the elements out of supermarket value kettles to make budget boilers. A fermenting bucket costs £8-15. If you've already got loads of glass beer bottles, a capper would be about £10, and caps a few pounds for a bag full. While you technically may not need a wort chiller (and we have not got one yet), I think it makes things much easier and potentially much quicker, and safer (there is less risk of other nasties infecting your brew if you can pitch your yeast as soon as possible). As for a mash tun, we're currently not using one and are mashing in a cloth bag directly in the boiler (much to the horror of our local brew shop owner).
Grain you're looking about £5 for a brew (if you buy in bulk), hops can vary depending on the recipe, but perhaps £1-10 (depending on the hops used and the amount required).
We went for this boiler while it is reduced (till early next month I think, but I can' remember the exact date)
http://www.nisbets.co.uk/manual-fill-water-boiler/CC193/xc-cc193/ProductDetail.raction and I didn't want to do DIY when it comes to mixing boiling hot sugary water and electrics.
For a less DIY kit, search on
www.brewuk.com for all grain starter set.
If you've got things from kit brewing, that's a good start. If you haven't, I'd maybe get that first, as you'll use it for all grain anyway.
Best Regards