OK, who here has any idea what bike the OP is starting with?
I've worked over a bunch of bikes in my time. I enjoy doing it and I generally encourage other posters to do the same. On the other hand, I also try to warn inexperienced posters to think through and to cost out a project before they spend ANY money. Once you get started buying components, every dollar that you spend makes it that much harder to walk away from buying one more part to make it work. Every dollar that you put into a crummy old bike is one more dollar taken out of your fund for buying the kind of bike that you really want.