Note: Salesforce has a standard VLOOKUP function but has limited functionality, this approach helps overcome those without code.

Process Builder and Flows are recent automation engines provided by Salesforce, they have been around for a while but haven't been used widely i believe (probably developers tend to stick with Apex Triggers and Workflow rules as they are used to it)

The use case below shows you how you could use these two together to solve a simple scenario which as a developer we tend to solve with Apex Code.

Scenario:

Everytime a Product2 record is updated, i have to query if this product exists in a custom object (Exempted parts) and based on the result update a boolean field on Product2.

Solution:

STEP 1:

Create a Flow (Product2_Validate_Exemption)

STEP 2:

Create a Process and call the flow every time a product2 record is updated.

Reference: This example uses the great search component provided by Avinava Maiti. His blog is here 
http://blogforce9.blogspot.com/

Problem:

Using a standard lookup field on the user object, Salesforce does not allow you to lookup a user who is of the license type 'Chatter Free'.

Solution:

Although you cannot use a standard UI to update the user lookup field with a chatter free user, you can update the field through the API. This means that we could use a visualforce page to populate the lookup field.

Assumptions:
We will use a custom type ahead advanced search component.
We will use a custom field 'Chatter Free user lookup' on the account object.

STEP 1:
Install the autocomplete search component from here

http://blogforce9dev-developer-edition.ap1.force.com/ProjectDetail?id=a0290000009KusM


STEP 2:

Create the following apex class


STEP 3: Create the following visualforce page:democustomlookup

STEP 4: Create a new custom button on the account object.
STEP 5:

Add this custom button to the page layout and you are done.

RESULT: