So DH and I have been talking about getting bikes...and then accessories so we can bike as a family of 4...

We have two girls almost 3 and 4.5 mos.

For experienced biking bees out there:

1) what is a realistic budget for bikes for Dh and I? Not looking for the rolls Royce of bikes - just something decent that is good quality since we'll be involving our girls.

2) which option for incorporating the girls? A seat in the bikes? (The I worry DD1 may outgrow this soon) or is a trailer thingy better?!?

In case it matters... We live in a suburban environment (rarely not in pavement or extremely pressed sand trails). DD1 is 26lbs...DD2 is 4.5 mos and has decent head control...