Here are some budget-friendly standing desks that can help support your posture and prevent backache:

 

1. SHW Electric Height Adjustable Computer Desk

2.VIVO Black Height Adjustable Standing Desk Converter

3.Nandi Electric Height Adjustable Standing Desk

4.Stand Steady Tranzendesk 55 Inch Standing Desk

5.FlexiSpot M2B Standing Desk Converter

6.ABOX Electric Powered Lifting Standing Desk Converter
 

These standing desks are designed to help you maintain good posture and prevent back pain while working. They come with adjustable height settings and other ergonomic features to allow you to work in a comfortable position. They are also budget-friendly, so you don't have to spend a lot of money to enjoy the benefits of a standing desk. However, it's important to note that while standing desks can help with posture and back pain, they are not a cure-all, and it's essential to incorporate other healthy habits such as regular exercise, stretching, and taking breaks while working.