12v to 15v DC to DC converter

Hello everyone, I'm looking for a circuit for a DC to DC converter circuit that inputs 12v and outputs 15v at around 3-4A. Can anyone suggest a way of achieving this without using an expensive IC? I'm on a tight budget you see. Thanks for any help

Define expensive.

Attached is the schematic of a circuit to convert 12V to 15V at 4A. I'm not sure what you consider expensive but the total BOM is $4.55 USD. The schematic was generated using one of the WEBENCH design tools on the National Semiconductor website. I've personally found it very useful in the past. Here's a link:

**broken link removed**

Ideally less than £20 ($30ish), and it would appear that vne147 has it more or less sussed! Thankyou very much!