I'm using Solr 1.4 and have defined the following field in schema.xml:
<field name="SALE_PRICE" type="sint" indexed="true" stored="true" />
With this query I get the expected items within the defined range (25000 to 30000).
http://localhost:8983/solr/select/?q=*%3A*&facet=on&facet.field={!ex=SALE_PRICE}SALE_PRICE&fq={!tag=SALE_PRICE}SALE_PRICE:[25000+TO+30000]
With ...