That's a pretty slim budget. Do you already have a power amp? If not your choices are even fewer and you're not starting with much in the first place.

What do you have now in the terms of speakers?

There is no such thing as mixing monitors for 150.00.

Auratones!

I have a 100 watt stereo pwr amp

If you buy second hand, you can probably get a pair of Tannoy reveal...for that kind of money.
It's not the best monitors, but at least it's much better than trying to mix with just headphones as you're doing now.
But I think that you should try to find a way to get at least 500 USD....then you will have many more options.

How much are those Yorkville Monitors? They're relatively inexpensive and they've gotten decent reviews.

i have heard good things about the Behringer offering, i think they are 300-400 a pair(powered).

150 will def not do it.

i had that budget to start and after hearing everything in stores i went with KRK V6's (800 usd pr.)

I just recived the new BSW catalog ... on the back cover is the EDIROL Amplifed Speakers... at $149. The ad says sold as a pair, I am not sure if this is a pair for $149.. Now in no way do I recomend these but if the price is for a pair, it falls into the parameters of the request you made. BSW also is offering the AUDIX PH5VS powerd monitors at $199 for a pair .. Hafler M-5 at $99.99 ea. (recomended by me). You can find BSW on the web at http://www.bswusa.com Kurt

Thanks Kurt I will investigate.

I've recently had the chance to hear the Audix line of monitors at my Local Professional Audio Magic Shoppe and I'm happy to report that they are much better sounding than any competeing monitors at that price..Smooth highs and a realistic lowend.Now I havent MIXED anything on them but the variety of music I heard pumped through em led me to believe that they would translate decently.AND they're made right here at home in Wilsonville Oregon...The mosels I heard were the N5's and the N10's....I have also heard the Haflers and can second Kurtenheimers recomendation......

I thought I'd jump in again... about buget monitors: Have anyone tried the ESI nEar 05 ?
Are they something worth trying out?