Gumtree etiquette

[Doyouknowwhat]

I've never used this before, but I've seen something that I might want to buy.

How does it work?
The seller had confirmed that it is still available. Do I get the chance to see it and then decide, or do I just have to agree and then buy it whatever condition it's in?
Do i pay cash when I collect it, or do I have to pay first?
Please help me with gumtee etiquette.
Thanks

Assuming it's relatively local to you I would say 'would I be able to come and have a look and if it's right I will take it'? Most reasonable people would say that is fine unless it's something small or self-explanatory that doesn't need a viewing... Will the item be transportable in your car?
It's a pain waiting for people to show up though just to look, so I would say normal rules of etiquette apply; be on time etc.
My experience of gumtree is cash on collection.

Thanks. It's a chair, I hope it would fit in my car, I'd be really embarrassed if I went to get it and it didnt.

You pay cash when you collect.

If it's a high demand item sellers might just want to sell to whoever can collect first, to take that into account when asking to view it first.

Pay cash on collection,
Turn up (lots don't),
It's OK to negotiate on price (but be realistic),
You can ask for measurements prior to viewing.

It's been on for over 2 weeks so I doubt there is much clamour for it. I've been truthful, explained my worry about the car, and asked if i can view it anyway.