Effusion Fragrance Lamp....help!

Does anyone happen to have an effusion lamp?

This is the glass container which resembles a lamp
but does not burn a flame to emit fragrance through
liquid. You fill the jar with liquid scent, cap it for 30
minutes, then let it burn for 3-5. Then you blow it
out and put a crown on instead of the cap.

My problem is that the liquid is rather high dollar
and doesn't burn long. It provides about an hour
of fragrance per ounce of liquid, with most of the
bottles running $14.95. Sure, the fragrances are
nice and smell wonderful - very much unlike the same
old standard scents from a box store such as
cinnamon, lilac, the standard.

However, as much as I love our home to smell good,
the price to operate this lamp is out of my budget.
I asked the lady at the company if I could burn anything
else in it, understandably she was hesitant to suggest
anything, though she did mention it would need to be
alcohol based. I figured that much, as fast as it burns.
The label states it is 90% isopropyl alchohol.

My question is, has anyone out there safely substituted
anything in their lamp, and if so, could you suggest a
good brand which offers good scents at a decent price?

Thank you so much for any assistance.

Karen