@Helen3 @Nathan92, at my listing, I try to maximize "comfort" for the lowest cost possible.
I provide no name bottled water in the fridge that I get for $1.89 a case.
I got "spa slippers" from Amazon and I put them in a nice big wooden bowl near the front door. Putting on slippers instantly puts you at ease and transforms you into relaxation mode. The slippers cost $2 a pair.
I buy small potato chips and granola bars in bulk and leave a few out in a basket. Cost $2
On reservations where the rate was higher or more nights booked, I'll leave a bottle of wine WITH a cork and not screw cap, that's $2.75 at the local grocery. The suggestion for "comment cards" is great. If you really want to know, just ask and the suggestion of spending $500 on some decor probably the best advice I've seen as it relates to your situation. So for about $8-$12 a reservation, I add "value". Try this and see what happens, buy a case of bottled water and put eight in the fridge. Get a case of Ramen noodles and put five packs in the pantry and I bet your guest comment on that all the time. My listing pics are old too but I'll put my listing up against any other listing in my market and I know I can compete.