There are several brands of pastel pencils, which come in various pack sizes - e.g. 12, 24, 36, and 72 pencils. Brands include: Derwent (I really like these), Faber Castell, and Gioconda - I have the 72 sets of both Derwent and Faber Castell. Be aware that these are Artists' quality materials and are priced accordingly - expect to pay approx. £1 per pencil. Jacksons Art has a good selection at reasonable prices, but they can be bought from Amazon or eBay, as well as other Art supply stores. Colours are fairly similar across brands, but of course the larger sets will have a good selection of colours, so it's best to buy as large as you can afford (pencils can also be bought singly). You will also need a method of sharpening, as ordinary pencil sharpeners tend to break the "lead", there are special sharpeners available, but I find a craft knife used carefully is easier (get a fine point by rubbing on fine-grade sandpaper). You might also like to try a proper pastel surface to work on, rather than paper, and Pastemat is wonderful - it has a velvety abrasive surface which grips the pastel or pencil for vibrant colour - again it is quite expensive, and may be above your budget, but do give it a try if you can!
Wow that's great thank you, good point about sharpener I woulnt have thought of that. Yes was going to go for a bigger set as I still want to use 72 colours in bigger chalks and think 24 will be frustrating to match. I wasn't sure about getting special paper but will give it go if you say so. Thanks again