If you want a high end laser only setup, go with Crimson Trace (grips) or Lasermax (guide rod). I'd imagine you can probably find either for a little under $300. These are spendy, but their value is that they minimally alter the feel and balance of your gun.
The other option is a rail mounted setup. Unless you want a tac-light, stay as small and light as possible. If you want a tac light/laser, I recommend the Sig Sauer STL-900L. Bright 130 lumen light, strobe, laser...and you can get it here for about $100+
cheaper than anywhere else I've seen.
Here's my P226 w/STL-900L. A little bulky, but a great nightstand setup.