Why are you offering salt? What deity is this for? If this is a way to offer flavour, table salt will do. Rock salt too. Pink salt can be used in love, so that would work well for a love deity. A salt lamp might symbolize healing. Overall, go with what you feel works best, since it is the thought that counts. If you feel the deity you are offering this salt to would be happier with one type over another, go with that. Be sure to record how you feel after the offering, and if you notice anything in the days that follow. This could be a sign to see if they liked or disliked the offering. You can also ask them which they prefer.
Which type of salt do you feel the particular deity would enjoy more?
Is the color pink acceptable for your own personal taste, example often I tend toward a basic white salt as to not interferre with my altar theme.
This next one can be important to consider. Do you wish to work with Fae? Himalayan salt has some iron in it. The Fae are not very fond of iron, so if you do intend to work with Fae it isn't the best idea to keep iron and things containing it around the area you intend to work with them. It may be better to set aside another small altar for them, iron free.
Other then that it is your personal preference. Which can you afford? Which helps you connect with deity?
Sea salt for a deity like Poseidon (God of the Seas and the Oceans). Pink salt for love deities. For spirits and deities associated with the Earth, rock salt I suppose, and maybe himalayan salt for mountain-based gods.
But if you are unable to find a specific salt or cannot afford it, don't worry. Most gods aren't that picky and will be fine with table salt.