It doesn't have to be leather. I also found it a tad toasty wearing leather during the heat of an Okanagan summer, so a couple of years ago I picked up a synthetic jacket ideal for summer riding. It was on sale at a local shop, don't recall the price, but probably not much more than you'd pay for used gear. It has plenty of zip vents & elbow pads for protection. Very windproof when all the vent zips are done up. As far as pants go, I often wear jeans but they offer little protection if you ever go down. I've been meaning to buy chaps, but not a fan of those really. I do have a full leather suit & another leather jacket that's pretty beefy for the cooler days. I usually wear the full leathers when I'm out on a longer trip on the highway. Feels a whole lot safer than a t-shirt & jeans, although I'm guilty in that regard as well if I'm just tooling around town. Neither of my bikes offer much in the way of windshield protection (I like 'em naked), so anything over 60 kmh, jeans & t-shirt don't cut it.
Anyhow, here's a photo of the synthetic jacket I'm talking about. I'm sure you can get something similar for a good price new to get you through the course & work on the leather goods later on. BMW also sells synthetic riding gear, but the price is too much for me to stomach, so "Shift" it is.
