Below are links to printmaking suppliers where you can source everything to make a linocut. This list is by no means exhaustive but they are the suppliers I use. If you can find others please let me know. Remember, it is not worth spending a lot of money buying the best if you are a beginner. I printed successfully for years using an old wooden spoon for a baren. I gradually improved my paper and inks and have only recently bought a hand made baren from Japan.

Paper
John Purcell Paper - A huge selection of printmaking papers including a whole section of Japanese papers. They do mail order and have sample books.
Lawrence - Smaller selection of japanese papers but a good selection of more general printmaking and exotic papers.
The Baren Mall - A network of printmakers that have an online shop and link to suppliers of japanese printmaker materials including 'proper' Hosho hand made paper. Expensive and worth it only for very competent printers.

Lino Sheets
Lawrence - Sell a variety of precut lino 3.2mm and 4.2mm thick. For the busy printer who needs a larger amount or different sizes it is economical to buy lino by the roll. Either 0.9m x 2m or 0.9m x 5m.
Great Art - Sell pre-cut lino sheets in sizes A5, A4, A3, A2 and A1. They also sell pre-cut Japanese plywood for woodcuts.

Inks
Lawrence - A good variety of oil based and water washable printing inks. Relief, engraving, etching and lithograph. Good value up to more expensive professional quality.
Great Art - Again a good variety of printing inks mainly at the value end of the market.

Barens
Lawrence - 100mm diameter traditional baren, quite soft and wears out after about 400 impressions. Excellent low to medium usage.
Great Art - Slightly larger and harsher than the Lawrence baren. Lasts longer but can damage delicate paper.
The Baren Mall - ooh lovely. Hand crafted and items of beauty themselves, Have a look through the website for a selection of different makers, types, sizes and prices. You may have to wait a couple of months while you order is made. I waited a couple of years to finally take the plunge (financially) and it was worth the wait for the difference it makes to colour saturation, especially when used with japanese paper.

Tools
Lawrence - A good selection of tools with cheap beginner sets, japanese style sets, student quality and more expensive artists quality tools up to £25 a gouge.
Great Art - Beginners box sets, individually priced tools and nicely displayed sets in wooden boxes. Up to around £9.50 a tool
The Baren Mall - Again the real Mcoy if you want to follow a japanese method of relief printing. Links to carving tool makers Shimizu Hamono and Michi Hamono (Hamono means literally things with blades) Traditional Japanese cutting tools in four varietys of blade. They also do sets of six to eleven knifes at around $150 to $280