Horrified, seeing a good hotel when budget's ending (6)
I believe the answer is:
aghast
'horrified' is the definition.
(thesaurus)
'a good hotel when budget's ending' is the wordplay.
'a good' becomes 'ag' (I've seen this in other clues**).
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'when' becomes 'as'.
'ending' suggests the final letters.
The last letter of 'budget' is 't'.
'ag'+'h'+'as'+'t'='AGHAST'
'seeing' is the link.
(Other definitions for aghast that I've seen before include "'Appalled, dismayed (6)'" , "Shocked, dumbfounded" , "Horror-struck" , "Horror-stricken, filled with consternation" , "Deeply dismayed" .)