how secure is sending values through urls in PHP

I want to know how secure is about sending values through URLs. It will be a big mess I think. The good suggestion would be sending values by post method in php through pages. But if I get a better example of how usually the script would be in po开发者_JAVA技巧st format it would be great.. Or otherwise suggest your valuable comments to this to do how

GET: User can directly see the data in the browser location bar.

POST: Anyone in the intermediate network between client and server can still see the data.

Solution: If you want ultimate security, you need to use SSL (HTTPS). It's not free, you need to buy the SSL certificate first.

[EDIT]: OP Clarification:

"Anyone in the intermediate network" means that suppose you are connected to your company's Internet Firewall that connects to to your Internet Service Provider (ISP) which connects to the server your website is hosted on.

Now, if you do not use SSL, then your company administrators can see the data through firewall and also ISP administrators can see it, if they want.