Resources for bulbs

Can anyone recommend some good resources for replacement bulbs? I have a Hayward fixture that takes one 500W type R-40 bulb. One store said it would be a 2 week wait and cost around $30. Its the first time we've replaced the bulb.

Also, the gasket seems fine - who do I know if I should replace it now?

Thanks everyone and have a Happy Fourth.

Not sure about source for bulbs but I believe that at every bulb replacement you need a new, fresh gasket.

If a gasket goes, does the bulb get ruined at the same time?