diff --git a/include/extern.h b/include/extern.h
index b2d15cb0d..d3ef197b9 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -2481,6 +2481,7 @@ extern void shopper_financial_report(void);
 extern int inhishop(struct monst *);
 extern struct monst *shop_keeper(char);
 extern boolean tended_shop(struct mkroom *);
+struct bill_x *onbill(struct obj *, struct monst *, boolean);
 extern boolean is_unpaid(struct obj *);
 extern void delete_contents(struct obj *);
 extern void obfree(struct obj *, struct obj *);
diff --git a/src/do.c b/src/do.c
index f5abe2537..1eb6581e9 100644
--- a/src/do.c
+++ b/src/do.c
@@ -134,7 +134,7 @@ boulder_hits_pool(
 
         /* boulder is now gone */
         if (pushing)
-            delobj(otmp);
+            useupf(otmp, otmp->quan);
         else
             obfree(otmp, (struct obj *) 0);
         return TRUE;
diff --git a/src/hack.c b/src/hack.c
index 9449529cd..2a6acc237 100644
--- a/src/hack.c
+++ b/src/hack.c
@@ -154,9 +154,9 @@ moverock(void)
     register coordxy rx, ry, sx, sy;
     struct obj *otmp;
     struct trap *ttmp;
-    struct monst *mtmp;
+    struct monst *mtmp, *shkp;
     const char *what;
-    boolean firstboulder = TRUE;
+    boolean costly, firstboulder = TRUE;
     int res = 0;
 
     sx = u.ux + u.dx, sy = u.uy + u.dy; /* boulder starting position */
@@ -243,6 +243,8 @@ moverock(void)
                 || doorless_door(rx, ry)) && !sobj_at(BOULDER, rx, ry)) {
             ttmp = t_at(rx, ry);
             mtmp = m_at(rx, ry);
+            costly = (!otmp->no_charge && costly_spot(sx, sy)
+                      && shop_keeper(*in_rooms(sx, sy, SHOPBASE)));
 
             /* KMH -- Sokoban doesn't let you push boulders diagonally */
             if (Sokoban && u.dx && u.dy) {
@@ -353,7 +355,7 @@ moverock(void)
                               (ttmp->ttyp == TRAPDOOR) ? "trap door" : "hole",
                               surface(rx, ry));
                     deltrap(ttmp);
-                    delobj(otmp);
+                    useupf(otmp, 1L);
                     bury_objs(rx, ry);
                     levl[rx][ry].wall_info &= ~W_NONDIGGABLE;
                     levl[rx][ry].candig = 1;
@@ -380,6 +382,8 @@ moverock(void)
                     if (ttmp->ttyp == TELEP_TRAP) {
                         (void) rloco(otmp);
                     } else {
+                        if (costly)
+                            addtobill(otmp, FALSE, FALSE, FALSE);
                         obj_extract_self(otmp);
                         add_to_migration(otmp);
                         get_level(&dest, newlev);
@@ -444,6 +448,14 @@ moverock(void)
             } else {
                 newsym(sx, sy);
             }
+            /* maybe adjust bill if boulder was pushed across shop boundary */
+            if (costly && !costly_spot(rx, ry)) {
+                addtobill(otmp, FALSE, FALSE, FALSE);
+            } else if (!costly && costly_spot(rx, ry) && otmp->unpaid
+                       && (shkp = shop_keeper(*in_rooms(rx, ry, SHOPBASE)))
+                       && onbill(otmp, shkp, TRUE)) {
+                subfrombill(otmp, shkp);
+            }
         } else {
  nopushmsg:
             what = the(xname(otmp));
diff --git a/src/shk.c b/src/shk.c
index e78e7a01d..866e2aebc 100644
--- a/src/shk.c
+++ b/src/shk.c
@@ -29,7 +29,6 @@ static const char the_contents_of[] = "the contents of ";
 static void append_honorific(char *);
 static long addupbill(struct monst *);
 static void pacify_shk(struct monst *, boolean);
-static struct bill_x *onbill(struct obj *, struct monst *, boolean);
 static struct monst *next_shkp(struct monst *, boolean);
 static long shop_debt(struct eshk *);
 static char *shk_owns(char *, struct obj *);
@@ -868,8 +867,8 @@ tended_shop(struct mkroom* sroom)
     return !mtmp ? FALSE : (boolean) inhishop(mtmp);
 }
 
-static struct bill_x *
-onbill(struct obj* obj, struct monst* shkp, boolean silent)
+struct bill_x *
+onbill(struct obj *obj, struct monst *shkp, boolean silent)
 {
     if (shkp) {
         register struct bill_x *bp = ESHK(shkp)->bill_p;