UPDATE:

Thanks Evan for your comments!!

In more recent versions of Flow, you can simply have your URL point to /{!RecordId} and Salesforce will correctly navigate to the record. Obviously, RecordId variable in the flow should hold the Id of the record. I did a quick check on this in my Dev edition org and it worked.

Here is how you can do it in the new flow builder:

Create a screen element with the Display text as Link(or whatever you name the text) and give the hyperlink as /{!RecId} where RecId is the flow variable which holds the Id of the created record or the Id of the record to be navigated to, after the user clicks on the Display text(Link). Screenshot is given below for your reference:

How to achieve this in Old Flow Builder:

For example, there is a flow which gets inputs from user and creates a RateCard(Custom object) record, if it doesn’t exist in the system. Once created, it should show the URL(clickable) of the record created.

This is possible by editing the screen(which is the last step in the flow) and the Display text field there is a little button which shows T(marked in yellow colour in the screenshot below) with what looks like a selection box around it. Type the text you want (View the RateCard record here). Highlight it, and in one of the fields that showed up you can put in the url,something like https://cs5.salesforce.com/{!RateCardIdcreated}

P.S: RateCardIdcreated holds the Id of the RateCard record created.

Please let me know your comments.