If you're not looking for any motion in the videos besides wipes and all you want is photos, music, text and audio -- you're looking at about $50. This is assuming you're using RF photos and music and no voice overs.
If you need VO then you're looking at a minimum of $25 for a professional VO but you can usually do this yourself. If it's your website your voice is preferred. Just record the message yourself in wav and ask the video producer to lay it into the audio track.
I'd be careful of anyone quoting you less than $50 because they're probably using pirated photos and music. Get caught and you're looking at multiple copyright infringements. The cheapest photos are about $1.00 each. figure about 20 photos for 30 seconds. Music runs about $10 to $35 on some stock libraries. Normal production is around $99 but I've seen a few people give this away at $50. Just depends upon the level of expertise.
Hope this helps....