If the shop is busy then they most likely don't want to mess with a low budget guy project. In my experience the low budget guys are the biggest pain to deal with. They fret over all the little stuff and since they can't afford the good parts you end up with a lower quality build. For example, the low budget guy will want to use $20 head gaskets rather than the $100 gaskets which work. Then they complain about leaks and want the engine torn down for no charge to replace the cheap head gaskets that they insisted on.

So it is very possible that if you went into an engine shop and spent some time talking about how you want it done really cheap that the owner just gave you a high price to get rid of you.

About the only way a low budget guy can get work done for a low cost is to go into a shop and tell the owner "I'm low budget but I"m not a loser. I want it done right but it is going to take me time to pay for this". An approach like that might work but if the shop is busy you might not ever get your job done either.

The other option is to save your money and wait for the next recession to hit. Then you can go in the door with cash in hand and you'll be king of the room.