Solid (site) gives AI agents their own computers, accounts, and budgets so they can build apps, automate workflows, and finish long-running jobs without a human at the keyboard. It's freemium with a $20 free trial, then paid plans start at $40/month (Starter), rising to $160/month (Pro) and $640/month (Max), all drawing from a single account balance for AI usage and machine costs. Below are cheaper alternatives that offer agents their own compute or workspace, listed from cheapest to most expensive.
| Product | Free tier | Starts at | Best for |
|---|---|---|---|
| Agent Sandbox | Yes | $0.00025/mo | Usage-based billing, no subscription |
| Computer Using Agents by LLMHub | Yes | $0.05/mo | Testing agent workflows cheaply |
| Construct Computer | Yes | $9/mo | Persistent agent processes with a desktop-style view |
| SolidAssist | Yes | $22.76/mo | Self-hosted, privacy-focused teams |
| SureThing.io | Yes | $30/mo | Agents that report results in plain language |
| Agently | Yes | $33/mo | AI agents embedded in a shared work OS |
| Openbase | Yes | Not stated | Open-source, voice-controlled agent management |
Agent Sandbox
Agent Sandbox gives each agent its own remote computer and drive, billed by the second. Pricing is pay-as-you-go: $0.00025 per second of compute and $0.0005 per MB of storage, with $10 in free credits for signing up via Google (agentsandbox.co). There are no subscriptions or commitments. It suits developers who want fine-grained, usage-based cost control rather than a flat monthly fee. The limitation: without a fixed plan, costs for long-running or heavy jobs are harder to predict than Solid's flat-tier model.
Computer Using Agents by LLMHub
This product runs agents on isolated computers that operate like a human user. It offers a free sandbox with pay-as-you-go pricing at $0.05 per managed step (first $5 free), plus a Developer plan at $19/month with $25 of API credit, and custom Enterprise pricing (coasty.ai). It's a good fit for developers who want to test agent workflows before committing to a subscription. The limitation: per-step pricing can add up quickly for complex, long-running jobs of the kind Solid is built for.
Construct Computer
Construct Computer is a cloud OS where persistent AI agents ("Constructs") live with their own compute, storage, and network identity, viewable through a desktop-style interface, with integrations across business tools (construct.computer). Pricing is freemium with a 7-day free trial on Pro, then Lite at $9/month, Starter at $39/month (annual), and Pro at $199/month (annual). It suits teams wanting persistent, observable agents similar to Solid's model. The limitation: matching Solid's full feature set likely means the $199/month Pro tier, not the $9 entry price.
SolidAssist
SolidAssist is an AI assistant that runs on your own server rather than a shared cloud account. It offers a 3-month free trial, then a Team plan at €19/user/month (about $22.76), with a minimum of 4 users for 3 months, plus custom Enterprise pricing (solidassist.de). It suits privacy-conscious teams that want self-hosted control. The limitation: the 4-user minimum makes it a poor fit for solo users or very small teams, unlike Solid's single-account plans.
SureThing.io
SureThing.io is an autonomous agent designed to communicate results the way a person would. It has a free plan with 1,000 credits (no card required), then Basic at $30/month, Plus at $60/month, and Pro at $200/month, with pricing based on monthly credits (surething.io). It suits users who want clear, human-style reporting from their agent. The limitation: as a credit-based system, heavy or long-running work may burn through credits faster than Solid's account-balance approach.
Agently
Agently is an AI Work OS combining documents, tasks, team chat, and integrations, where AI agents operate inside a shared workspace with persistent memory (agently.dev). It has a free tier (100 credits, 1 app, no card), then Starter at $33/month billed annually ($390/year), Pro at $83/month, and a top tier at $166/month. It suits teams that want agents working inside existing project and document workflows. The limitation: the advertised low prices require annual billing, and no plain monthly rate is stated.
Openbase
Openbase lets you manage a team of AI agents by voice from anywhere, distributed as an open-source GitHub project with a macOS app (openbase.cloud). It suits technical users comfortable self-hosting and experimenting without a vendor contract. No pricing information is stated on the site, so cost commitments beyond your own infrastructure are unclear. The limitation: without stated pricing or a commercial support plan, it's harder to budget for compared with Solid's tiered subscriptions.
How to choose
If you want to pay only for what you use, Agent Sandbox or Computer Using Agents by LLMHub keep costs near zero for light workloads. If you want a persistent, observable agent environment closer to Solid's own-computer approach, Construct Computer or SureThing.io are the nearest matches. If self-hosting or workspace integration matters more than raw compute ownership, look at SolidAssist or Agently. Openbase is worth checking only if you're comfortable with unpriced, open-source software.
FAQ
Is any alternative actually cheaper than Solid's $40/month Starter plan? Yes, all seven listed here start below $40/month, several with usage-based pricing well under $1.
Do these alternatives give agents their own computer like Solid does? Agent Sandbox and Construct Computer explicitly provide agents their own machine or persistent compute environment; the others focus more on workflow or workspace integration.
Which option has no stated price at all? Openbase has no pricing information published, unlike the other six alternatives.