Hi Ryan
The one square yard things smacks with clients of the old Kirby cleaner salesman. I'd be careful with that on domestic clients.
Commercial clients will expect you to clean a larger area as a demonstration. If it's a large enough potential job then we usually offer to do the whole Reception IF, AND ONLY IF they have already agreed that the price for the rest of the clean is what they are prepared to pay, ie they are likely to pay your price in future. The worst that happens is you get the odd one scam you for a free clean of the Reception and then says you're too expensive for the rest of the job. For those that think you're too expensive anyway, they don't get a free cleaning demo. There are other ways to play this too. If you're more expensive than others you can offer a demo clean and if the results are better than they expected, or usually get, then you get the rest of the job at the price agreed. OR you can even offer to do the clean for your higher price and if they genuinely can't see any difference between your clean and their usual contractor you will charge them what they usually pay. You have to be prepared to take a risk, you get stung now and again but has worked for us.
Al.