Appliances are being delivered to my home.

Here's my thoughts, FWIW:

If it's a big refrigerator (or the like) and an easy delivery, I find that $10 suffices. If you have a tough entry or tricky stairs, then $20. If it's around Xmas/holiday times, definitely give a tip; however, if they're putting their hands out expecting or even demanding it, then no way! I've seen that and it's tacky.

If this is any help to you, the cheaper the appliance store's prices, often times that means that they pay their help with low wages. Let your conscience be your guide.

They'll install the gas oven and I'll install the microwave myself.

So $10.00 a piece is enough?

sure thing. That's fine.

Of course if the oven blows up and levels your house then all bets are off!