I only have the "Pearl" which is a double. I have never seen the single offered. Al

I bought some from ebay. It was about $11.5 including shipping. I was pleasantly surprised by the generous amount of bulbs. I potted them up about a month ago and I see several shoots have emerged already. I have kept them indoors until the weather warms up.
I have read that the single are more fragrant than the double. Its the singles that are used in making perfumes.

This site sells them.

Here is a link that might be useful: Easy to Grow Bulbs