In recent years my hotel/motel lodging budget has been about $50 per night, and I have booked the majority of my nights away online through Booking.com. I usually succeed in adhering to this price point except on holiday weekends, in the vicinity of major metropolitan areas like Chicago, or (occasionally) no-notice arrivals in strange cities where I have failed to explore the lodging options online. I often find myself staying in many motels that are clearly doing a stint in independent ownership while (as Briantroutman puts it) awaiting the wrecking ball, but I have never had any problems with lumpy mattresses, unclean laundry, bedbugs, cigarette burns, etc. The furniture is often mismatched and uncomfortable, and the walls tend to be covered with heavy textured plasticized paper that is designed to cover up gouges and small holes and to be easy to wipe clean with a wet cloth, but these do not bother me since I feel I am failing to take advantage of the opportunities for experiential enrichment inherent in travel if I use the motel as anything but a place to rest my head, shower, and possibly update a travel journal.
The last time I allowed myself to be ambushed by high motel prices, I was at a Super 8 in Sault Ste. Marie (Canadian side) where I paid US$92 because I had my phone in airplane mode and so had no easy way to identify lower-cost options. In retrospect I would have been much better off if I had paid $2 for Canadian roaming that day; for a little over half that cost I could have stayed in a much more characterful hotel in downtown Sault that was also much closer to the International Bridge. I did recognize that the bedding, towels, furniture, and wall finishes in the room were of much higher standard than in the $50/night bracket, but the utility I get out of these things (while on the road) is much less than is the case for other affluent middle-class travelers.
In the past (early noughties), I stayed in hot-pillow motels, motels that had visible cigarette burns in the bedding, motels with visible and olfactory evidence of past occupants' sexual activity, etc., but this was at a time when it was not nearly as easy to identify budget accommodation online as it is now, and it was necessary to rely on broad-brush strategies (e.g., "find the bypassed city routing of a current or former US highway") that let the really sketchy establishments into the picture. I suspect the increasing use of online booking has had a ratcheting upward effect on amenity standards in the budget sector, because a motel is more likely to find customers if it is discoverable online, but grossly unfavorable reviews (as opposed to penny-ante stuff like "Disappointing," "Interior looked cheap," "Clerk was surly," etc.) on booking sites tends to scare off drive-up business that has the ability to check reviews on a smartphone before stepping into the office to book.
As is the case elsewhere in the real estate sector, the three most important factors when looking for accommodation are location, location, and location. While my hotel/motel budget is $50 per night, I put hotels and motels in the same basket as campgrounds, hostels with dormitory accommodation, bedrooms in private houses found through Airbnb, etc. and I go for whichever has the commanding advantage in cost in a given area. In Duluth this meant staying in a campground on a rainy weekend night because a tent site was $32 while motels (aiming at Twin Cities weekenders) were $150 or so. In Marquette, Michigan, I stopped at an Econolodge with an almost-empty parking lot just to explore how stratospherically unreasonable the rates were ($129/night), before I went to the city campground where I pitched my tent for $27 with electric. On the other hand, if a given area has motels for under $50, I am not going to search hard for campgrounds just to eke out a further $20-$30 for the day. (I estimate that camping costs me about one and a half to two hours in time compared to staying in a motel, because on arrival I have to pitch the tent, inflate the air mattress, and lay out the sleeping bag and pillows, while on departure I have to fold up the sleeping bag, deflate the air mattress, collapse and pack the tent, and load the trunk; in addition to the time required for these tasks, there is also much lost time and motion dealing with my toiletries in a shower hut rather than an enclosed attached bathroom. Rain adds greatly to the time and comfort penalties. My tent is waterproof with a rain cape, but also does not breathe that well, so besides having to have plastic grocery sacks handy to keep my wet footwear from soiling the tent floor, I have to endure the smell of my own sweaty feet. And when I pack up the tent, I have to take pains to dewater it as much as possible so it doesn't mildew in the bag.)