IT depends what you count as "macro" a lot of things that are called macro are not, true macro photos. For example most butterfly, flower and dragonfly photos are not macro photos strictly speaking.
As for lens costs - this gets very grey and you've got to decide on your own priorities. For some getting a cheap versatile lens helps them make the right choices on the expensive stuff later on - for others they already know what they want and just need to get there. The 70-300mm can do shots like this:
as well as hit the 300mm mark, its softer at the long end (there is a slightly more expensive, but noticeably better APO version of that lens with a red ring around the rim which has improved optics).
whilst a "true" macro lens can do this:
Maybe you only want to take pics or flowers or wildlife and the hoverfly is of little interest to you - or it might be that the hoverfly is everything. Deciding which is important to you is the key. Also the sigma is a great experiment lens - you can play with long range; with close up and see if it takes your fancy before following a more expensive route.