In reply to Mr Winkleberry:
I should really be recommending that you visit our shop and buy some from us... But since you've mentioned you're on a budget, check out somewhere like Machine Mart for ground anchors. I've seen that they have a similar thing pretty cheap. You'd have to check what they were rated to, but the concept is pretty much the same.
Make sure you have a steel bar about 1m long to place/remove them.
Not sure about A-frames though, I think it would be possible to make some similar to the ones from Slackline Tools.
Hope this helps!