There's a limit under the Texas rules, something like $30. Check the TALCB website for exact details. It is against the law for kickbacks, etc for appraisals, but they allow for small gifts as I recall.
I am going to say this off the top of my head without looking since it is late and I just walked in I am tired. I think USPAP says something to effect that it is OK as long as the gift is within what would be considered normal business.
Assuming you are talking something like 20-30 dollars I wouldn't think that would be an issue (state laws aside). As long as no one could say and it look as if you were offering bribe or a kickback I believe you don't have a problem.
I like to give a nice bottle of wine but quite honestly...hasn't been necessary lately since everyone is so busy. Berringer's White Zin, about $5 when on sale. Top it with one of those little Christmas bows and your business card.
Something that was very sucessful in the past was having a lunch catered in for the office. This is a little more expensive but usually leaves a lasting impression. Show up before the catering truck and give everyone a sales pitch then have lunch with them. Costs between $10 to $15 a person. If you really want to go all out, call a local music teacher and find someone who can come in and play violin for an hour. Be sure to include the secretaries in the deal.
Have a summer BBQ in a park. Invite several different mortgage brokerages who then can compete in volley ball, soft ball or lawn darts, etc. Beer n Brats type event.
Going to repeat my favorite, compliments of my sister. Mason jars filled with M & M's. Create some labels on your computer...a business card that looks like a jar label. On it say....."I will refill the jar every time I deliver an appraisal".