Yeah. I normally just buy the rolls because I like to change it out every couple of times. Probably not needed that often, but I am just kinda weird that way. Last roll I got was 20 feet for a little over 7 bucks at Lowes.
Above is great advice. Usually if they get to funky I just go get another section at Lowes or Home Depot. You can get rolls of tubing or get it cut by the foot. Might be a buck or so if you go by the foot.