For running clothing, wear something loose and comfortable like a t-shirt, jogging trousers or tracksuit. Socks are very important part of running clothing to prevent blisters. You don't need to buy expensive purpose made socks but you need to use a thick comfortable pair to provide a protective layer between your foot and the shoe. Investing in a good sports bra as part of your running clothing that you buy will be well worth it. Sport shops and department stores will have a good selection to choose from, a particularly good brand is shock absorbers. Use extra layers in colder weather, these can be taken off as you heat up. Since most body heat is lost through the head and hands it is important for comfort to wear a hat and gloves. Try to wear trousers made of nylon and lycra and avoid trousers with polyester as this causes discomfort when sweating. For safety it is very important to be visible on dark nights, wear bright colors or invest in a fluorescent vest or band for around your arms and waist.
IT IS NOT NECESSARY TO BUY EXPENSIVE CLOTHES - THE MOST IMPORTANT ITEM IS SHOES.
Go to your nearest running shop and have a gait analysis done. This will determine how you run and the most suitable shoes for you. Support in the right areas of your foot is critical for running to prevent injury. Pay particular attention to shoes providing cushioning, arch and heel support to prevent the foot turning in and out. The wrong shoe can add to injuries such as shin splints and knee injuries and is therefore well worth investing in a good pair that will last.