But if you take slowboy's SV650 for example, which is an excellent little sports/road bike, it's really good value when you consider that Suzuki did little in the way of development on that model during its life - so a much later or even new SV will ride and feel very similarly to a 1999 bike. When that happens, you'd might as well save cash and buy the old one, especially if you find one with incredibly low mileage like this (how on earth has it only racked up 600 miles in 20 years?).
OK, it's not a cheapie, like £500 cheap, but a quick search on ebay shows that you really can't get much more than early chinese cheese-framed rubbish for that money, or a jap bike basically for parts only.
The trick to finding good really low-price hack bikes, IMO, is to get rid of any idea of buying an iconic or popular bike. You may have to abandon pretensions of slick-handling cool looking bikes, but you can save a fortune. So if you want a 600cc for road use, forget an R6 and buy a GSX600F Teapot. They have a dull reputation, so just £800 will buy you this:
https://www.ebay.co.uk/itm/Suzuki-gsx60 ... SwoS9fwkqY
A good R6 of the same era (5eb / 5sl) will cost £2-£2.5k. And if you only truly want to get to work and back, or if you want to ride through winter, the teapot would be better probably.
There are loads of other examples like this, where casting off fashion and optimal handling can save a lot of cash, to spend on tyres and fuel. An old UK mate of mine recently had £3-£4k to spend on a litre sporty-ish bike and asked me to look on ebay. He was looking at MY2005 Fireblades and such like. But he's not a natural sports bike rider and I knew he wouldn't use the performance of a CBR1000RR, so I pointed him to a nice silver 2003 Triumph Daytona 955i which he fell in love with and bought for £1900. Suits him down to the ground, does maybe 70% of what the Blade can do on most roads and costs less to insure. He's about to buy a DR350 and some dirt-kit with the money he saved.
