To echo what many have said, actually to shout what many have said,
'If you want to catch fish, Get a Guide!'. New or experienced Fly Fisherman on a heavily fished (or lightly for that matter) Western trout stream will tell you that a guide is the only way to go. You state you are new to fly fishing, so there is no way you can have experienced the difference in fishing with or without a guide. Many of the fly fishermen here will attest to their experiences trying to fish a new water without a guide verses with a guide.
A guide is Worth The Money,
if you wanna catch fish, if you just want to play around and have a good time in the outdoors then do so and have a great time.
I do not believe that rerigging a spinning rod and then try fly casting with it will work, not well any way. I stand to be corrected but that is not a good option and really do not see it casting a fly at all. Consider that if that were the case, rerigging a spinning rod to fly we would all be doing it, and I have never seen that done.
If you do get a guide, he may have all the equipment you need and no purchase necessary. If you get hooked on fly fishing that starter combo for under a $100 will very quickly become a garage sale item. You get what you pay for, I would take cupofjoe04's very kind offer to borrow equipment rather than waste the $100, put those bucks toward a guide.
One Note: Western Trout are treated like Gods of the Water, they are NOT treated like bass or pan fish in Texas are treated. Net them, take a picture in the net in the water and quickly release them, picking them up out of the water, spending 10 minutes taking pictures passing the fish around and them throwing them back in is a Big NO NO and may arouse strong feelings if there are other fly fishermen in or near you.
Gig'em, Ole Army Class of '70