Rockie - I lacked the circular saw as well and did just fine. I didn't have one and really don't like using one so I just did work arounds...
Remember that the lumber yards will cut wood to any size you need. I always took in my list of exactly what I needed cut out of what. I did layouts in advance and placed things for maximum coverage..sewing skills in doing fabric layouts helped there...
They used to charge a buck after the first cut but the last few times I've used H/D for multiple cuts they've not charged me at all...guess it depends on who you get and how busy they are...maybe whether they're in a good mood too...
Take a look at my build thread and you'll see that I mostly managed to hide any bad squiggly cuts by planning ahead....
Using the jigsaw takes a little bit of practice. Most of the trick is in using the right blade for what you're cutting. I picked up a package that had all different blades in it and they were labelled as to what they were for.
I also swear by the use of the Kreg Jr. kit for screwing things together. It's my favorite tool!