If you order through Amazon, almost everything you buy can be accomplished through AmazonSmile and Shelter Care will get a percentage of the dollars you spend.
Sign into smile.amazon.com and you will be prompted to select a charitable organization from their list of eligible charities (Shelter Care is on their list). 0.5% of your purchase will be donated to Shelter Care by Amazon.
From then on you just enter the Amazon site through smile.amazon.com or bookmark it for easier access.
See the graphic below for first-time users of AmazonSmile.