Student or Learner
Do we say
I made a small contribution OR I made a little contribution.
Your cat is very small.
Can I have two small pizzas please?
We can use little to refer to size, but we usually use it with another adjective to express an emotion.
You're a silly little boy.
Nobody's looking after that poor little dog.
In comparative and superlative form, small is more common in British English, and little is more common in American English.
That's the smallest phone I've ever seen. (British English)
That's the littlest phone I've ever seen. (American English)
SO, your first sentence is correct.
All contributions, no matter how small, will be much appreciated.
Hope this helps!