I got a puncture about 2 weeks ago on my last ride before leaving for vacation, so I've only gotten back now and I'm looking for some tips on getting it fixed.
Everyone told me "bummer, there's another tyre down the drain" which pisses me off, cos I probably have less than 300 km's on the current tyre.

What should can I do? Looks like you can just repair the innertube, which means you just pay for labour? I can inflate my tyre at a petrol station, and it keeps fine for a couple of minutes (till I get home) but it's not going to last a day.

Can I simply spray slime or some of that other foam in? and then inflate? or is it best to take it to the shop and pay them to do it?

It looks like mechanikal_vandal got it sorted pretty easily though?

I wouldn't spray anything in a tyre, if you ever had to scrape the mess that slime stuff deposits on your inner rims once it's dried up, you will understand.

Tyre repairs rules of thumb are as follows:

If the hole is in the midde of the tyre thread and one inch away from the edge of the tyre, then by all means get a new tube or patch the one you've got, provided the hole is not too big, in which case you don't need to bother about plugging the tyre either. Result!!

If the hole is larger than a 1/4" screw, have the tyre plugged by qualified brain surgeon (tyre repairman). However... if the hole is on the edges of the tyre wall it's bye bye nice tyre, no decent repairmen would recomend you to continue to use that tyre ever again because weakening the tyre wall beeds can result in a disatrous blow out at speed and you don't want that.

Safe rather than sorry is your only choice.