Jessica,

I don't want to get the "walmart" argument started again here, but if your budget only runs to about $300, walmart sells a kent tandem that would accomodate you for less than that figure. We have one that we've had for going on 3 years, we ride it about 25 or 30 miles a week, sometimes more. My wife is barely 5 feet tall and I'm 6-1. There was enough adjustment in the seats and handlebars to get us both comfortable. We've even crashed it a couple of times, but it comes right back. Have had no repairs to do on it other than the crash related stuff. Are there better bikes out there? Absolutely. And if you can find them for what you have available to spend, by all means get the best you can afford. If not, the Kent would make a good first tandem for you.

Good luck in your search and have fun riding!