Sale price is actually $2.99 (save $1.00), but if you buy 10 or more, you save an extra 25%.
If you're fortunate enough to live in NSW, free pickup is available from their store in Blacktown. I bought 10 units and shipping to Adelaide via Fastway was $10.90, bringing the total to $35.99. This is a lot cheaper than buying on eBay or Amazon, typically around $46-$49 for 10.
Prices for refills from supermarkets are generally in the $5.00-$6.00 range, although I haven't seen these two fragrances. They may be an exclusive import which might explain the RRP on the Superbuys Warehouse website as being $3.99 per unit.
If you purchase less than 10, the price is still relatively cheap at $2.99 each.
Also, if you haven't got the spray unit, or you want an extra one, they have the Clean Linen one on sale for $3.99 (save $2.00).