In case you are planning to buy a bike and that to a budget bike, Please check the on road milage first. You would not like to spend a big bug filling fuel every day.
Go with a brand which is well established brand like Hero or Honda. This will help you get better after sales service as well.
So things to check before buying a Bike
Is the Brand Established?
Is there a support centre near your house?
Kitna deta hai?
Storage and comfort
Looks.
Hope this helps.