Hi msprotege,
I don’t know prices off the top of my head (you would need to check the websites of the other manufacturers or retailers on the list) but there would be many that are in a lower budget range than the Tempflow Eros.
While most memory foam (or gel memory foam) mattresses will tend to sleep warmer than most other types of mattresses … unfortunately there is no specific comparative testing or scientific information available that compares different mattresses in terms of sleeping temperature so outside of the knowledge and experience of a manufacturer or retailer and making general comparisons between the types of materials in a mattress, it’s not really possible to predict or compare how warm or cool any specific mattress will sleep for any specific person except based on personal experience because there are so many variables and subjective factors involved (including where you are in the “oven to iceberg range”). There is more about the many factors that can affect temperature regulation in post #2 here and more about different ways that can be used to cool down memory foam mattresses in post #6 here (memory foam in general tends to sleep warmer than other types of foam) that in combination with your conversations with each manufacturer and your “best judgement” can help you make a more informed choice about whether a mattress will be “cool enough” for you regardless of how cool or warm it may sleep for someone else.
The better options or possibilities I’m aware of that are reasonably local to you would be in the Providence list in post #4 here or in the list for the Boston region in post #2 here (which includes a manufacturer in Fall River and in New Bedford).
Phoenix