An easy way to avoid buying new running gear is to take care of the things you already own. For technical fabrics, wash them in cold water and hang to dry rather than putting them in the dryer.
To prolong the life of your running shoes, consider alternating two pairs. And if a pair of shoes gets wet, stuff them with newspaper and put them in a sunny spot; never put them in the dryer. Heat can shrink the upper material and break down the outsoles.