You know that the purchase cost of the bike is just the start. Then there's rego, insurance, maintenance (even if you do it yourself, oil and parts cost money) and fuel.
Then there's riding gear. A set of ATGATT (all the gear all the time) will be some hundreds of dollars, but you do need good boots, gloves (if you fall off you WILL put your hands out!), some kevlar reinforced jeans, jacket and, most importantly, a good helmet.
I picked a 300 sports bike rider up off the road and took him to hospital, he who was only wearing flip flops, shorts, a tee shirt and a helmet and had come off at a round about (traffic island) on a diesel spill at only 30 km/hr (20 mph) or so - you do NOT want to go there! Could see the knee cap bone (or is it actually cartilage? it's white anyway), minced up toes, he wasn't going to be using his hands for quite some time, and red stuff was oozing through his ripped tee shirt and shorts.
Good that you've saved up some money, and I do recommend buying a second hand bike too. The absolute best learner bike is a 250, lighter, easier to handle, cheaper 2nd hand and resaleable. As well, you'll probably want to upgrade after a year or so whatever you start on. I did 20 months/24,000 km (15,000 miles) on a 250 learner cruiser when I started riding at 61, best decision I made.
And do the MSF course!!!! Can't emphasise that more.