Many stores take a 15% cash deposit (or whatever your tax amount is) so that their tax payments to uncle sam are covered.
Layaways should be used when deposits are made but the goods do not leave the store until paid in full. Accounts Receivable should be used when credit terms are given and the goods will leave the store before the item is paid in full. This is a basic accounting principle. I've never heard of a situation where this is handled differently. If you stray away from this method, your inventory will be inaccurate and it can be a nightmare to try and resolve discrepencies.
If I come to you on Monday and want to buy a TV, but I won't pay for it until Friday, then you have to decide if I'm going to be able to take the TV out of your store today or on Friday. If I can't take the TV until you've received all the money for it, then that's a Layaway; meaning I'm going to give you a deposit so you hold that TV for me and I'll come back on Friday to pay the balance and take the TV with me.
However if you're going to let me take the TV today, but I won't have to pay for it until Friday, then that is an Accounts Receivable which should be tendered as a Sales Transaction and paid for On Account. It's up to you have I must make an initial cash payment or not. Generally, if you deal with consumers then you will take a cash payment up front, but if you deal with contrators, wholesalers and other businesses, then you do not take a cash deposit unless they have defaulted on their credit terms in the past (of course this just a general practice, but everybody has their own policies)
I'm not an accountant, so I'm not sure what the tax implications are on Layaways vs Accounts Receivable. I believe that you pay tax when the goods are delivered, but having A/Rs might balance this out.