Is there any way to avoid paying US$18 for Lancôme's hot Fall 2009 polish color, Indigo Paris?  Yes and no.  Let me explain...

I decided to compare nine polishes to Indigo Paris to see if I had any dupes. IP is just so glowy yet dark, vibrant and alive! I don't regret getting it, but I also love and wear a lot of blues. So here's how the other blues I swatched (two coats of polish plus topcoat except where noted) compare:

On my left hand, I had:

Thumb- Lancôme Indigo Paris

Love this color!

Index- MAC Naughty Nautical

NN is a smidge darker than IP and less glowy, but it's my 2nd place pick as a dupe for IP.

Middle- Wild and Crazy Cuidad Victoria

CV is lighter with more uniform frost/shimmer. I had to do three coats of this one. Definitely not an IP dupe.

Ring- Quirius 430 Moody Blue

MB is a touch darker and not as glowy as IP, but very close. This is my first place pick as a dupe. MB was also opaque at one coat, but I did two out of habit.

Pinkie- Misa A Sin Worth Committing

ASWC is lighter and more aqua than IP, with lighter blue shimmer.

Left hand pictures:

On my right hand, I had:

Thumb- Chanel Blue Satin

BS has a darker base and darker shimmer than IP. It's a more subtle polish.

Index- Essie Midnight Cami

MC has a dark base like Blue Satin, though not as vibrant. The shimmer is more aqua than IP, and harder to see.

Middle- Revlon Midnight Affair (old version)

MA's shimmer is more aqua, and it has a more blackened blue base versus IP. The shimmer is also more twinkle-y (possibly bigger) versus a more uniform pearl/frost.

Ring- China Glaze Up All Night (non-Big 3 free version)

UAN has a darker base and darker shimmer, but it's still close to IP. This is my third place pick for an IP dupe.

Pinkie- Maybelline Acoustic Azure

AA is in a more blackened aqua base, so I don't think it's a good dupe.

Right hand pictures:

Mixed pictures:

In the first two pictures, I have my right ring finger over my pinkie.  The order, from the thumb to the "pinkie"/ring finger, is Lancôme Indigo Paris (thumb), MAC Naughty Nautical (index), Wild and Crazy Cuidad Victoria (middle), Quirius Moody Blue (ring), and China Glaze Up All Night ("pinkie"/ring finger.)  In the bottom picture, I put my China Glaze UAN right hand ring finger underneath my left thumb.

Basically, it boils down to this- if you want Indigo Paris (and you have the moolah), I say get it!  If you have a large stash and don't want to buy another polish, look through your stash for China Glaze's Up All Night.  If you want a cheap dupe, try Quirius' Moody Blue.  (I paid US$1.75 for it, I believe.)  If you're a MAC fan, see if you have Naughty Nautical.  If not, your local counter or CCO may have it if they're on the slow side at moving previous collections out.  But I definitely think Indigo Paris is worth the money.