Spend what you want to spend on a bike. I've had great service from cheap bikes which don't have suspension. A few key cheap upgrades can transform them. It's really down to how you use the bike if its just on the road and a few gravel tracks etc a simple reliable bike is all you need and the weight varying by a few kg is not a huge issue. Remember a expensive mountain bike is designed for extreme off-road use and a super lightweight road bike is designed for competitive fast riding. Don't be ashamed of a cheap bike often they make the most sense for general cyclists but if you want a high end model go for it.