How to create Listing in ebay sandbox?

I am working with EBAY [REST API]. For this i am using SANDBOX [which is test enviornment of Ebay]. I have created a developer account and two sandbox test user.For acting as a buyer and seller.I am trying to create listing using seller account. i created the product in the inventory but when i publish offer it gives me error and i could not publish the offer. it give me error like create policies etc.

I want to create a product using seller account and then buy tht product using buyer account.

Is there any other way to create listing ?

I am following this : https://developer.ebay.com/devzone/guides/features-guide/content/basics/Call-SandboxTesting.html

Since you have not specified the exact error you are getting when making the publishOffer call, I will try to outline the whole process for reference. The prerequisite steps for publishing an offer from your sandbox account are:

1. Create Payment, Fulfillment, and Return policies for your sandbox account. For this, you may call their respective APIs or you can use their API Explorer which has sample policy requests ready to be executed or, easiest of all, you can manage your business policies from the sandbox website here
2. Create your inventory item using createOrReplaceInventoryItem call
3. Create an inventory location for the created item through the createInventoryLocation API call. Your offer won't publish without this.
4. Create an offer for the inventory item. Specify the offer details, such as fulfillment, payment, return policy IDs, category ID, inventory location ID, etc
5. Publish the offer

There are quite a few requirements, specific to the type of item you are providing through a listing, that you have to fulfill before eBay will let you publish the offer. You can find more information about this in the error response you get when publishing the offer.

With that said, eBay's sandbox has behaved very unreliably in the past from my experience. So if you are doing everything right and still running into problems, as a last resort, you can try creating the listing by using eBay's Trading API's AddItem call. I have personally found these sets of eBay APIs to be more reliable (albeit more outdated).