1) Make a bed that has the soil that plant prefers and do not amend it.
2) Many people with clay soil edge their planting beds with a "Victorian Edge" a trench that seperates the planting bed from the lawn. That trench, for the most part, stops the grass from growing into the bed because grass roots will not grow in the presence of too much air. Filling the trench with something would be counter productive.
3) Never, ever just "dump" any organic matter from your premises, always find a way to recycle that stuff. Even "weeds" have taken up nutrients from your soil and throwing them away simply removes those nutrients which means you need to spend money to buy more, if you can.
4) All you can do is ask. Often you will be told no.

Some comments on #3 and #4:

3) If any of the weeds are currently in seed, they should be hot composted or thrown away, otherwise by throwing them directly on the bed you are sowing a weed crop. If they are the kind that spread by roots/rhizomes (ivy?) I would also hesitate to mix them directly into the bed.
4) I use a cheap machete for chopping things to be composted...picked it up at an army surplus store years ago and it works great. I think it really helps tough things like corn husks to be chopped up a bit.