Do your research !! We took a semi private tour by Greyline in Budapest and it was great. I know you want to do self guided, but consider this - for what its costing to get there, what's another $100-200 ? Time is money. Time spent aimlessly wandering around town is wasted $$. My wife insisted on a guided tour and she was right ! Great way to to get the lay of the land and learn where all the major sites are and then you can back track on your own (that's what we did). You should always google for tour company reviews. On the other hand, we jumped on a 3 hour "English" language tour in Prague at the spur of the moment only to find it was also in German and Czech. In other words, 70% of the time, you had no idea what they were saying and the 30% you did hear, you could have learned from any tour book. Total waste of $150. By the way - scams abound in Prague - especially in the tourist area restaurants, so be careful. They have a lot of very inventive ways of inflating the bill. Go outside Old Town ie, New Town and prices plunge. Restaurants aren't as fancy, but at least the bill is correct and the food is great.