Populate fields with custom fields values

I am new to gravity forms and I must first admit that its awesome!
I've been working on my first form for a while and everything seems working great expect one last function I am trying to execute with no success so far.
I've 10's of pages with 5-10 products per page, each product's name & price is defined in custom fields as:
item1, price1 - item2, price2 - item3, item4- .......
Assuming that item1 & price1 values are: example_product & $99
In my form I've 2 hidden fields that can populated dynamically named 'name' & 'price', when I link to my form page from the products' page using this link (example.com/form-page?name=example_product&price=$99) and submit the form, entry successfully and store both 'example_product' and '$99' values and I can find them stored in the database without any problems.
Now, rather than injecting the values of product name and price to 100's of links for 100's of products in each single page, I am after an easier way to auto get the custom fields values automatically and populate these 2 hidden fields within my form, I've searched through the form and the documentation for a solution and didn't found anything but this:
http://www.gravityhelp.com/forums/topic/using-custom-fields-to-populate-hidden-fields
I've tried the solution posted there but didn't worked for me, he have his form in the same page contains the custom fields, while for me they are 2 different pages, didn't worked for me because of that? maybe!
BTW, if you'd be able to add the ability to populate the fields with chosen custom fields from origin post as within the default value option it gonna be one very amazing added features to gravity forms, personally, I'd love to see such a feature soon to save myself sometime, maybe someone's time in the future too :)

Thanks for your reply David, it didn't worked :(
However, again, here's what I am trying to do, I've simplified the process to the max:

In my site I've 2 pages, page A and page B:
- Page A contains some products I am selling, lets say 2 products, xproduct and yproduct
- Page B contains an order form made using Gravity Forms

- Page A have 2 custom fields contains the product code of these 2 products as following:
-- Custom Field #1 >> name: xcode, value: p1xcode
-- Custom Field #2 >> name: ycode, value: p2ycode
- Page B have 1 hidden field named code populated automatically by the (?code=value) in the incoming URL

- When customer would like to purchase xproduct from page A he click a 'Buy Now' link next to it, where this link do contain the (?code=p1xcode) and forward to page B, the form filled successfully with the hidden filed populated with 'p1xcode'
- Same thing applies to the other product, so, when customer would like to purchase yproduct from page A he click a 'Buy Now' link next to it, where this link do contain the (?code=p2ycode) and forward to page B, the form filled successfully with the hidden filed populated with 'p2ycode'

I believe its so clear so far, and everything is working great till here
What I want to do is: Instead of hard-coding (p1xcode) and (p2ycode) manually for all 'Buy Now' links for each individual product, I'd like the hidden field in gravity form to AUTO get the value of specific custom field in the origin page
So:
Instead of "?code=p1xcode"
It'd be "?code=custom_field_name" ... (or whatever tweak of code it takes)
The Result: Hidden Field in the Gravity Form populated with the value of that custom field automatically
What we are talking about here is NOT only Page A, but 10's of pages ALL pointing to the same page/form for completing the purchase...

I believe I made it simple enough and explained the whole process, don't know if this is enough and achievable of not, but hopefully it is :)

Thanks for your reply Carl

As I stated earlier, I've already followed the same steps you posted here, and again it works only if I inject the value in the URL myself, the code listed in the other thread as stated before would work ONLY if you have the form in the same page, not in a separate page like my case here
However, I managed to find a solution myself and it worked, in case anyone here like to do the same, use a plugin called "Custom fields shortcode" it would let you get any custom field value using a simple shortcode and it worked for me with less code effort
This thread can be marked as resolved now :)